• 


NOTES  ON 
FIELD  FORTIFICATION 

BY  THE 

ARMY  FIELD  ENGINEER  SCHOOL 

THE  ARMY  SERVICE  SCHOOLS 


FORT  LEAVENWORTH,  KANSAS 

1914 


NOTES   ON 
FIELD    FORTIFICATION 

BY    THE 

ARMY  FIELD  ENGINEER  SCHOOL 

THE  ARMY  SERVICE  SCHOOLS 


FORT  LEAVENWORTH,   KANSAS 

1914 


Press  of  the  Army  Service  Schools 
Fort  Leavenworth,  Kansas 


Preface 

"Field  Fortifications  are  a  means  to  an  end.  In  conjunction  with 
maneuver  and  fire,  they  constitute  an  instrument  of  tactics,  and  should  be 
employed  only  when  and  where  required  by  the  tactical  situation."  (Quo- 
tation from  French  Manual.) 

"Field  Fortifications  are  always  of  use,  never  hurtful,  when  they  are  well 
understood."     (Napoleon's  103d  War  Maxim.) 

/*~P  H  E  above  quotations  set  forth  very  clearly  the 
-^  legitimate  role  of  Field  Fortifications  in  military 
operations,  and  their  appreciation,  when  properly  em- 
ployed, by  the  greatest  soldier  the.  world  has  yet  pro- 
duced. 

The  '  'Notes  on  Field  Fortification"  was  first  is- 
sued in  1912,  having  been  prepared  by  the  Director 
and  Instructors  of  The  Army  Field  Engineer  School 
for  use  in  the  course  given  the  student  officers  of  The 
Army  School  of  the  Line.  The  object  is  the  inculca- 
tion of  correct  views  regarding  the  employment  of 
Field  Fortifications  by  combat  branches.  It  is  in  no 
sense  a  manual  of  military  engineering  or  a  treatise 
on  fortification;  but  merely  enunciates  certain  prin- 
ciples which  are  to  be  amplified  in  the  class  confer- 
ences and  their  application  taught  by  terrain  exer- 
cises. 

No  solutions  of  map  problems  are  issued  with  the 
'  'Notes, "  as  it  is  not  believed  that  the  subject  of 
Field  Fortification  can  be  satisfactorily  handled  ex- 
cept with  the  ground  actually  before  the  student. 

The  original  edition  having  been  exhausted,  ad- 
vantage is  taken  of  the  necessity  for  reprint  to  make 
changes  which  the  use  of  the  book  in  the  instruction 
of  the  three  classes  and  the  progress  of  the  past  two 
years  have  indicated  to  be  desirable. 

M.  L.  WALKER. 
Major  of  Engineers, 


Chapter     I 

GENERAL  PRINCIPLES. — FIELD  FORTIFICATIONS  IN  RELATION 

TO  STRATEGY  AND  TACTICS.— SIMPLE  RIFLE 

TRENCHES. — LOCATION  OF 

TRENCHES. 

T  N  all  contests  for  the  mastery,  whether  between 
-•-  individuals  or  between  aggregations  of  individ- 
uals, there  is  an  inevitable  combination  of  offensive 
and  defensive  action.  Neither  contestant,  however 
great  be  his  superiority,  can  afford  to  neglect  all  de- 
fensive precautions.  This  applies  with  particular 
force  to  the  game  of  war,  in  which  the  contestants 
are  represented  by  armies,  often  of  huge  size,  oper- 
ating over  vast  areas. 

In  military  operations  the  advantages  sought  by 
each  side  are,  in  the  first  instance,  strategical;  in  the 
second,  tactical.  The  attainment  of  either,  or  both, 
necessarily  implies  possession  of  the  power  of  maneu- 
ver. The  advantages  attained  by  strategical  maneu- 
vers are  generally  realized  only  by  winning  the  bat- 
tle, which  is  their  culmination,  and  for  which  ability 
to  maneuver  tactically  must  be  maintained. 

The  power  to  maneuver,  whether  strategically  or 
tactically,  is  essential  to  success.  The  side  which, 
from  any  cause,  loses  the  power  of  maneuver  in 
strategical  combinations  will  be  at  a  disadvantage  in 
the  decisive  battle.  If  it  further  loses  the  power  of 
tactical  maneuver,  final  defeat  is  inevitable. 

As  maneuver  is  necessary  to  success,  troops  should 
welcome  orders  to  advance  from  the  trenches.  Chang- 
ing conditions  of  the  conflict  have  in  the  past  fre- 
quently led  to  the  construction  of  trenches  without 
their  being  used,  and  officers  must  expect  this  as  a 
5 


feature  of  campaigning,  and  accept  cheerfully  what 
at  times  may  appear  as  unnecessary  labor. 

That  offensive  action  alone  can  produce  decisive 
results  is  clearly  established  by  military  history,  and 
all  military  teachings  are  in  complete  accord  on  this 
point.  "Troops  dig  because  they  are  forced  to  halt, 
they  do  not  halt  to  dig. "  (Normand.)  But  while  act- 
ing generally  offensively  oneself,  it  is  none  the  less 
necessary  to  guard  against  the  enemy's  offensive 
movements,  and  this  can  be  most  effectively  accom- 
plished by  limiting  his  power  to  maneuver.  The 
means  most  commonly  employed  to  this  end  are 
fortifications,  which  have  for  their  object  the 
strengthening  of  the  terrain  at  predetermined  points 
in  such  manner  as  to  permit  relatively  small  forces  to 
check  the  movements  of  the  adversary  while  at  the 
same  time  facilitating  and  increasing  your  own  ma- 
neuver power.  Only  those  -fortifications,  conceived 
and  applied  in  this  spirit  are  really  useful  in  the  con- 
duct of  military  operations. 

According  to  whether  they  respond  to  strategical 
or  tactical  needs,  fortifications  may  be  classified  as 
strategical  fortifications  and  tactical  fortifications. 
Strategical  fortifications  are  most  frequently  con- 
structed, in  whole  or  in  part,  during  time  of  peace, 
with  all  the  resources  of  the  technical  arts,  to 
strengthen  points  whose  strategical  importance  in 
the  event  of  war  is  clearly  seen.  Occasionally,  how- 
ever, the  necessity  for  strategical  fortifications  arises 
only  at  the  outbreak,  or  during  the  progress,  of  a  war 
to  strengthen  points,  the  strategic  value  of  which  could 
not  be  foreseen.  Their  construction,  more  limited  as 
to  time,  involves  expedients  less  comprehensive  than 
in  the  case  of  works  built  during  time  of  peace,  but 
still  far  in  excess  of  those  applicable  in  ordinary  field 
works.  Strategical  fortifications  are  also  called  Per- 
manent and  Semi-Permanent  or  Provisional,  accord- 


ing  to  the  time  of  their  construction  and  the  materials 
employed.  The  various  existing*  land  fortifications  in 
Europe  are  examples  of  permanent  fortifications, 
while  the  defenses  of  Washington,  D.  C.,  in  1861-65 
form  a  good  example  of  provisional  fortifications. 
Both  permanent  and  provisional  fortifications  are 
constructed  by  military  engineers,  mainly  with  civi- 
lian labor  and  will  not  be  further  considered  in  these 
'  'Notes. " 

Tactical  fortifications  are  such  as  are  generally 
constructed  by  the  troops  themselves  to  satisfy  pass- 
ing tactical  needs.  The  time  and  materials  available 
for  their  construction  vary  between  wide  limits,  from 
the  hasty  intrenchment  built  with  the  portable  tools 
of  the  troops,  not  infrequently  under  fire,  to  elabor- 
ately fortified  lines  of  defense  requiring  days,  weeks, 
or  even  months  for  their  preparation,  in  which  work 
the  civilian  population  may  sometimes  be  employed, 
as  was  done  by  the  Russians  in  Manchuria  and  the 
Boers  in  South  Africa. 

Tactical  fortifications  being  constructed  in  the 
field  to  satisfy  temporary  tactical  needs  are  also  prop- 
erly called  field  fortifications.  It  is  well  to  observe, 
however,  that  the  various  classifications  of  fortifica- 
tions attempted  by  different  authors  are  not  always 
clearly  defined.  Strategy  and  tactics  frequently  blend 
into  each  other  and  so  do  the  fortifications  constructed 
to  meet  their  needs.  Similarly,  classifications  based 
on  the  time  and  materials  of  construction  employed, 
imperceptibly  merge  into  one  another.  Sometimes 
hasty  works  commenced  on  the  field  of  battle  are 
gradually  developed  into  stronger  ones  in  response  to 
the  tactical  situation  as  occurred  with  both  the  Rus- 
sian and  Japanese  lines  on  the  Shaho  and  with  the 
Turkish  lines  at  Plevna. 

*Refers  to  those  existing  before  the  outbreak  of  the  Euro- 
pean War  of  1914. 


—8— 

These  notes  will  deal  mainly  with  tactical,  or 
field  fortifications,  this  being  the  type  which  most 
directly  concerns  combat  officers  of  all  branches  of 
the  service. 

As  previously  stated  the  object  of  all  fortifica- 
tions should  be  to  check  the  adversary's  power  of 
maneuver  with  relatively  small  forces,  while  at  the 
same  time  facilitating  our  own  maneuver.  To  sur- 
render our  own  power  of  maneuver  is  either  an  ad- 
mission of  weakness  justified  only  in  the  presence  of 
superior  forces  and  resorted  to  for  the  purpose  of 
gaining  time;  or  else,  the  result  of  the  failure  of  the 
commander  to  appreciate  the  part  played  by  fortifi- 
cations in  tactical  opperations.  Unless,  therefore, 
the  adversary  is  overwhelmingly  superior,  field  forti- 
fications must  be  employed  in  a  manner  not  to  kill  the 
offensive  spirit. 

The  conception  that  field  fortifications  can,  and 
should,  play  a  part  in  offensive  operations,  although 
long  recognized,  was  brought  into  great  prominence 
in  the  recent  campaign  in  Manchuria,  especially  on 
the  part  of  the  Japanese,  who,  while  making  free 
use  of  field  fortifications  of  all  kinds,  never  relaxed 
their  aggressive  spirit;  on  the  one  hand  clinging  des- 
perately with  the  spade  to  what  they  had  won  with 
the  rifle;  and  on  the  other  hand  checking  with  their 
rifle  the  Russian  attempts  to  drive  them  from  their 
works.  Troops  acting  offensively  cannot  continue  to 
advance  constantly  at  all  points  of  an  extended  bat- 
tlefield where  fighting  is  carried  on  for  days.  Halts 
will  be  inevitable  from  time  to  time  at  various  points 
to  permit  assembling  forces  for  further  efforts,  to 
cover  the  mass  of  the  attack,  to  choose  the  point  of 
the  attack,  or  to  hold  the  enemy.  At  all  these  halts 
the  offensive  will  wish  to  hold  his  ground,  for  which 
purpose  the  strengthening  of  the  terrain  is  desirable 
and  necessary. 


To  derive  the  maximum  benefit  of  field  fortifica- 
tions, especially  in  offensive  operations,  requires  a 
thorough  understanding  of  their  application  in  ac- 
cordance with  correct  and  definite  principles.  Too 
early,  too  extensive,  and  too  frequent  use  of  field 
fortifications  are  certain  to  injure  the  offensive  spirit 
of  leaders  and  troops,  sacrifice  the  maneuver  power 
and  surrender  tactical  advantages  to  the  adversary. 
On  the  other  hand,  a  total  neglect  of  the  benefit  to 
be  derived  from  the  employment  of  field  fortifications 
will  involve  needless  and  heavy  losses  and,  against  a 
skillful  adversary,  will  lead  to  disaster.  Just  where 
and  to  what  extent  to  use  field  fortifications  in  tacti- 
cal operations  without  impairing  the  offensive  spirit 
is  often  a  delicate  and  difficult  matter  to  decide;  for 
this  reason  the  art  of  applying  hasty  field  works  is  one 
of  the  most  important  and  difficult  branches  of  the  en- 
tire subject  of  fortification.  This  is  all  the  more  so 
for  the  reason  that,  although  all  troops  are  now  lib- 
erally supplied  with  tools  for  the  construction  of  field 
works,  it  is  a  fact  that  little  attention  is  devoted  to 
this  important  subject  in  peace  training.  Duties  illy 
learned  in  peace  training  will  surely  not  be  well  per- 
formed under  the  stress  of  war. 

The  most  recent  wars  have  left  no  doubt  as  to 
the  extensive  part  played  by  fortifications  in  field 
operations,  fortifications  which  must  be  constructed 
by  the  troops  themselves  at  all  times  and  under  a 
variety  of  circumstances,  requiring,  therefore,  good 
understanding  on  the  part  of  all  officers  and  training 
on  the  part  of  the  enlisted  men. 

Since  the  object  of  field  fortifications  is  to  check 
the  enemy's  maneuver  power  with  relatively  small 
forces,  it  is  pertinent  to  inquire  just  how  this  result 
may  be  accomplished.  In  any  combat  the  primary 
object  is  to  gain  superiority  of  fire  by  means  of 
which  the  enemy  will  be  compelled  to  yield  ground, 


—10— 

either  by  the  fire  itself  or  by  the  bayonet  in  the 
hands  of  the  troops  whose  advance  has  been  rendered 
possible  by  this  fire. 

Superiority  of  fire  depends  upon  many  factors, 
such  as  the  character  of  the  fire  arm,  training  of  the 
troops,  size,  vulnerability  and  visibility  of  targets; 
but  mainly  on  the  relative  number  of  weapons  em- 
ployed. It  is  obvious  that  advantage  in  numbers 
may  be  offset  by  some  of  the  other  factors  mentioned. 
Thus,  troops  firing  from  behind  cover  are  decidedly 
less  visible  and  less  vulnerable  than  troops  in  the 
open.  A  man  standing  and  facing  to  the  front  pre- 
sents about  nine  square  feet  of  vulnerable  surface, 
while  in  the  prone  firing  position  he  presents  but 
little  more  than  two  square  feet  in  the  open.  Firing 
from  behind  cover  the  vulnerable  target  of  a  rifleman 
becomes  less  than  one  square  foot;  so  that,  other 
things  being  equal,  one  rifle  behind  cover  would 
roughly  be  able  to  cope  with  two  rifles  firing  from 
the  open.  Other  factors  affecting  the  fire  superiority 
of  troops  behind  cover  as  compared  with  those  in  the 
open  are  the  larger  advantage  of  the  former  in  the 
matter  of  ammunition  supply,  preparation  of  fore- 
ground, knowledge  of  ranges,  better  communications, 
measures  for  concealment,  and  possibility  of  reinforc- 
ing the  firing  line  under  cover.  By  a  scientific  and 
skillful  manipulation  of  all  available  means  of  fortifi- 
cation, troops  behind  cover  can  check  the  advance  of 
an  adversary  many  times  their  number. 

It  is  therefore  evident  that  superiority  of  fire  is 
not  only  a  question  of  the  relative  number  of  weapons 
brought  into  action  but  also  of  their  relative  fire 
effect,  and  that  fortifications  afford  the  means  for 
bringing  about  equality  of  fire  effect  between  forces 
numerically  unequal.  Any  device  or  artifice  which 
lends  itself  to  diminishing  hostile  fire  effect  therefore 


—11— 

constitutes  an  element  of  fortification  and  may  be 
employed  either  by  the  attack  or  the  defense. 

However,  the  advantages  of  fortification  will 
accrue  in  a  much  greater  degree  to  the  troops  on  the 
defense  since  they  can  select  and  prepare  their  field 
of  fire  so  as  to  give  the  fullest  effect  to  their  weapons 
and  prepare  better  cover  for  their  fire  lines  and  sup- 
ports while  the  troops  of  the  attack,  being  necessarily 
on  the  move  must  content  themselves  with  such  nat- 
ural cover  as  the  terrain  affords  or  with  the  very 
hasty  and  limited  works  that  cannot  be  constructed 
with  their  portable  tools. 

Unless  fire  superiority  has  been  attained  the 
attacking  troops  cannot  advance  and  their  intended 
tactical  movement  is  checked.  This  is  the  time  for 
the  commander  of  the  defensive  troops  to  reap  the 
advantages  which  his  field  fortifications  have  con- 
ferred and,  if  he  correctly  understands  the  game,  he 
will  pass  to  the  offensive  with  his  reserves,  which  he 
has  been  able  to  spare  for  this  purpose,  attacking 
vigorously,  while  the  enemy  is  more  or  less  exhausted 
and  used  up  by  his  previous  efforts.  It  is  only  by 
putting  into  execution  such  an  aggressive  action  that 
he  can  avail  himself  of  the  benefits  to  be  derived 
from  the  employment  of  field  fortifications  on  the 
battlefield  of  today.  To  continue  a  passive  defense 
must  certainly  lead  to  defeat  by  an  energetic  enemy, 
who,  failing  in  his  efforts  to  dislodge  the  adversary 
from  his  fortifications,  will  maneuver  him  out  of 
them,  or  avoid  them  in  the  first  instance,  if  they  ap- 
pear too  strong  to  attack.  The  latter  consideration 
leads  to  the  conclusion  that  it  would  be  a  mistake  to 
prepare  too  strongly  a  battlefield  position  whereon  a 
decisive  action  is  sought,  for  the  enemy  will  then 
simply  maneuver  and  all  preparation  will  have  been 
in  vain. 

From  the  foregoing  observations  we  may  rightly 


-12- 

deduce  the  following  general  principles  regarding 
the  employment  of  fortifications  in  connection  with 
tactical  maneuvers: 

1.  The  employment  of  field  fortifications  implies 
a  defensive  attitude,  but  only  a  temporary  one;  they 
must  never  be  permitted  to  impair  aggressive  action. 

2.  Field  fortifications  constitute  a  means,  coor- 
dinate with  maneuver  power  and  fire  effect,  for  the 
attainment  of  tactical  ends;  their  correct  employment 
therefore  constitutes  an  essential  part  of  the  subject 
of  tactics. 

The  mere  construction  of  field  fortifications  is  a 
comparatively  simple  matter,  the  knowledge  of  which 
is  easily  acquired.  Their  correct  tactical  application 
is  an  exceedingly  difficult  subject  and  calls  for  the 
exercise  of  the  highest  judgment  on  the  part  of  troop 
leaders.  In  the  modern  battle,  with  its  extended 
front  and  long  duration,  the  ever-shifting  phases  of 
the  combat  will  afford  frequent  opportunities  for  their 
application  upon  the  part  of  all  leaders,  from  the  com- 
mander-in-chief  down  to  the  company  officers.  Ordi- 
narily, technical  advice  and  technical  assistance  will 
be  impracticable  under  the  condition  of  the  rapidly 
shifting  events  of  the  battlefield,  and  this  fact  re- 
quires that  combat  troops  themselves  be  able  to  or- 
ganize field  works  to  suit  the  exigencies  of  the  occa- 
sion. All  combat  officers  should,  therefore,  possess  a 
good  understanding  of  the  part  played  by  field  forti- 
fications in  military  operations,  know  where  and  when 
to  use  them;  and  the  troops  themselves  should  be 
trained  in  their  construction. 

Simple     Rifle     Trenches 

Superior  fire  effect  being  the  primary  object  of 
all  tactical  operations,  the  fullest  possible  scope  must 
be  given  to  the  weapons  employed,  which  are  the  gun, 


—13— 

machine  gun,  and  rifle.  Although  of  the  greatest 
importance  in  diminishing  hostile  fire  effect,  cover 
must  never  be  permitted  to  interefere  with  the  fire 
effect  of  our  own  weapons.  Perfect  cover,  while  ob- 
tainable in  practice,  is  therefore  inadmissable  since 
no  fire  can  be  delivered  from  it.  The  use  of  the 
weapon  requires  either  that  it  should  be  capable  of  fir- 
ing over  the  cover  or  through  an  opening  made  in  it, 
either  of  which  involves  a  certain  area  of  vulnera- 
bility, which  area  should  of  course  be  made  as  small  as 
practicable. 

In  the  use  of  existing  and  specially  constructed 
cover,  the  consideration  of  the  free  and  unrestricted 
use  of  the  weapon  must  always  be  kept  in  view,  as 
this  determines  the  organization  of  the  cover.  In 
field  fortifications,  natural  topographical,  or  existing 
artificial  features  will  be  used,  ordinarily,  to  secure 
cover,  provided  their  location  is  suitable  for  good  fire 
effect.  They  not  infrequently  offer  better  cover  with 
less  preparation  than  is  possible  with  specially  con- 
structed cover  and  include  such  features  as  ridges  of 
ground,  banks  of  water  courses,  road  embankments 
and  cuts,  walls,  property  inclosures  of  all  kinds,  quar- 
ries, etc.  In  thickly  populated  countries  such  features 
occur  in  great  abundance  and  their  employment 
largely  reduces  the  necessity  for  specially  constructed 
cover.  In  sparsely  settled  country  the  necessity  for 
constructing  cover  is  more  frequent  and  the  method 
of  providing  it  will  now  be  considered. 

The  requirements  to  be  filled  by  any  cover  are 
readily  deduced  from  a  consideration  of  the  objects 
to  be  attained.  As  already  pointed  out  it  must  permit 
the  most  effiective  use  of  the  weapons  employed.  In 
addition,  it  should  afford  the  maximum  material  pro- 
tection against  the  enemy's  projectiles  of  every  kind, 
should  be  as  inconspicuous  as  possible,  and,  finally, 


—14— 

should  be  capable  of  easy  and  rapid  construction  with 
the  available  means.  Guns,  machine  guns  and  rifles 
require  different  forms  of  cover  to  suit  their  special 
dimensions  and  methods  of  use.  We  will  consider,  for 
the  present,  cover  for  riflemen  only,  the  rifle  being 
the  main  weapon  of  the  offense  and  defense. 

The  form  of  cover  best  adapted  for  the  riflemen 
and  best  fulfilling  the  requirements  above  specified 
is  the  result  of  experience  and  reasoning.  This  form 
will  naturally  be  subject  to  variations,  both  in  the 
manner  of  its  execution  and  in  its  final  dimensions, 
depending  upon  available  time,  tools,  and  material. 
Hasty  cover  prepared  on  the  field  of  battle,  in  the 
immediate  presence  of  the  enemy  and  frequently  un- 
der fire,  will  necessarily  be  more  limited  as  to  dimen- 
sions than  cover  constructed  with  more  deliberation. 

In  order  to  permit  the  most  effective  use  of  the 
weapon  the  soldier  should  be  able  to  adopt  a  com- 
fortable firing  position  behind  the  cover.  This  require- 
ment is  fulfilled  by  a  standing  position  with  a  firm 
support  for  the  rifle  and  calls  for  about  4'  6"  relief, 
between  the  top  of  the  cover  and  the  surface  upon 
which  the  soldier  stands.  This  relief  may  be  secured 
by  raising  the  top  of  the  cover  to  a  height  of  4'  6" 
above  the  natural  surface  of  the  ground,  or  by  lower- 
ing the  surface  upon  which  the  soldier  stands  an  equal 
distance  below  the  surf  ace  of  the  ground,  or  by  a  par- 
tial combination  of  the  foregoing  methods.  The  con- 
sideration of  being  able  to  overlook  the  foreground 
dictates  that  the  top  of  the  cover  should  rise  some 
distance  above  the  surface  of  the  ground,  whereas  the 
consideration  of  inconspicuousness  dictates  that  the 
heighth  of  the  cover  above  the  natural  surface  of 
the  ground  shall  be  as  small  as  possible.  Considera- 
tions of  speed  and  ease  of  construction  dictate  that 
the  necessary  difference  of  elevation  between  the  top 


—15— 

of  the  cover  and  the  surface  upon  which  the  soldier 
stands  shall  be  secured  by  a  partial  elevation  of  the 
former  and  a  partial  depression  of  the  latter.  These 
considerations  conflict  more  or  less,  with  the  result 
that  the  adopted  forms  are  compromises. 

The  thickness  of  cover  desirable  is  such  as  to 
secure  protection  against  all  projectiles  of  the  enemy, 
and  it  therefore  becomes  a  factor  of  the  penetration 
of  the  projectiles  in  use.  Experiment  has  shown  that 
3'  thickness  of  ordinary  earth  is  proof  against  all  rifle 
and  shrapnel  bullets,  but  that  to  stop  light  field  gun 
projectiles  a  thickness  of  from  9'  to  12'  is  necessary 
and  still  greater  thickness  for  the  projectiles  of 
heavy  field  guns. 

The  following  table  gives  the  penetration  of  the 
modern  small  arm  rifle  bullet,  caliber  30,  at  400  yards: 

Penetration 
Material  in  inches 

Dry  pine 34" 

Dry  oak 25" 

Dry  loam 30" 

Gravel  or  broken  stone 9" 

Snow,  lightly  compacted 90" 

Brick  work 15" 

It  is  manifest  that  it  will  generally  be  beyond 
the  power  of  the  troops  to  provide  specially  con- 
structed cover  of  sufficient  thickness  to  resist  the 
penetration  of  artillery  projectiles  and  this  condition 
must  be  accepted.  The  danger  from  this  source  is, 
however,  trifling,  for  cover  constructed  with  due  re- 
gard for  inconspicuousness  affords  so  poor  a  target 
that  few  hits  will  be  secured.  A  well  placed  projec- 
tile will  not  destroy  more  than  a  yard  of  cover  and 
will  reach  but  a  single  man.  According  to  French 
artillery  officers,  it  is  estimated  that  but  one  shot  in 
ten,  even  in  well  regulated  artillery  fire,  will  produce 
a  hit;  and  that  1,000' rounds  would  be  required  to  de- 
stroy a  simple  infantry  parapet  100  yards  long.  This 
would  practically  exhaust  the  entire  ammunition  sup- 


—16-- 

ply  of  a  field  battery,  and  as  there  will  be  miles  of  cover 
on  an  extended  battlefield  no  such  expenditure  of  artil- 
lery ammunition  can  be  entertained.  As  aptly  ex- 
pressed by  General  Langlois,  "firing  against  rifle 
trenches  with  artillery  shell  would  be  like  trying  to 
kill  flies  with  a  war  club"  and  with  all  the  chances  of 
failure.  Furthermore,  the  greater  portion  of  the  am- 
munition of  a  light  battery  consists  of  shrapnel,  and 
the  practicability  of  effective  fire  against  trenches 
is  thus  largely  reduced. 

If,  therefore,  the  cover  provides  protection  against 
rifle  and  shrapnel  bullets,  little  need  be  feared  from 
artillery  projectiles.  The  protection  of  rifle  trenches 
depends  far  less  upon  their  strength  than  on  their 
slight  command,  good  concealment,  and  dispersion  of 
the  targets.  The  parapets  should,  however,  keep  out 
rifle  and  machine  gun  bullets  which  are  responsible 
for  85  to  90  per  cent  of  all  casualties.  Parapets  that 
do  not  keep  out  rifle  bullets  only  serve  to  deform  them, 
making  them  capable  of  more  serious  wounds. 

The  simplest  and  most  usual  form  of  cover  for  the 
rifleman  is  the  simple  standing  trench  shown  in  Fig. 
1,  Plate  I.  It  will  be  noted  that  the  elevation  of  the 
cover,  commonly  designated  as  the  parapet,  is  L'  above 
the  natural  ground  surface  and  that  the  bottom  of  the 
excavation,  called  the  trench,  is  3'  6"  below  the  ground 
surface,  thus  affording  the  requisite  difference  of  ele- 
vation, or  relief,  for  the  convenient  use  of  the  rifle  in  a 
standing  position.  The  area  of  the  excavation  is  ap- 
proximately equal  to  the  area  of  the  parapet,  thus 
satisfying  the  requirement  of  the  maximum  rapidity 
of  construction.  The  top  of  the  parapet  is  practically 
horizontal  for  a  distance  of  three  feet,  insuring  pro- 
tection against  the  penetration  of  rifle  and  shrapnel 
bullets,  while  its  outer  slope  is  quite  flat,  facilitating 
the  harmless  richochet  of  artillery  projectiles.  The 
side  slopes  of  the  trench  and  the  interior  slope  of  the 


—17— 

parapet  are  held  as  steep  as  the  nature  of  the  soil  will 
permit,  while  a  small  berm,  1'  wide  and  1'  high,  is 
left  between  the  parapet  and  trench  to  serve  as  an 
elbow  rest  for  the  rifleman  and  as  a  place  to  store 
ammunition.  The  trench  is  furthermore  made  as 
narrow  as  possible,  reducing  the  amount  of  excava- 
tion and  diminishing  the  exposure. 

This  trench  (Fig.  1)  best  fulfills  all  the  require- 
ments sought  for  in  hasty  cover  for  the  rifleman  and 
is  the  form  generally  adopted  by  all  armies.  It  can 
be  constructed  in  practically  the  same  time  as  the 
kneeling  trench,  and,  as  it  affords  better  facility  for 
the  use  of  the  rifle  and  better  cover  for  the  man, 
should  be  followed  in  all  normal  cases.  Slight  modi- 
fications may  at  times  be  desirable  or  necessary;  to 
secure  a  somewhat  higher  parapet,  to  better  enable 
the  foreground  to  be  overlooked,  to  suppress  the  par- 
apet for  better  concealment,  or  to  provide  for  the  con- 
tingency of  difficult  soils  preventing  a  depth  of  trench 
as  great  as  3'  6".  Modified  forms  of  the  simple  rifle 
trench  are  shown  in  Figs.  2,  3  and  4,  Plate  I,  and 
their  construction  is  obvious  from  the  figured  dimen- 
sions. 

The  cross-sections  of  trenches  as  shown  are  called 
profiles.  Although  accurate  dimensions  are  given, 
these  need  be  adhered  to  only  approximately  in  prac- 
tice, especially  in  hasty  work.  It  is  important  that 
the  relief  of  the  trench  be  suited  to  the  stature  of  the 
individual  rifleman,  who  should  look  out  for  this  him- 
self. 

These  simple  trenches  constitute  the  main  ele- 
ments of  the  defensive  organization  for  infantry  in 
situations  calling  for  the  execution  of  hasty  cover. 
By  resting  his  rifle  on  the  parapet  and  his  elbow  on 
the  elbow  rest,  the  man  need  expose  but  little  more 
than  his  head  while  in  the  act  of  firing,  and  by 
crouching  down  or  sitting  on  the  bottom  of  the 


—18— 

trench  he  will  be  practically  safe  from  ordinary 
shrapnel  fire  and  shell  fragments. 

In  average  soil  the  trench  can  be  constructed  in 
one  and  one-half  hours  with  the  portable  entrenching 
tools.  Slight  as  such  trenches  may  appear,  they 
afford  a  material  increase  of  resisting  power  against 
troops  in  open  terrain  and  are  practically  indestructi- 
ble by  artillery  fire.  Their  very  slightness  is  an  ele- 
ment of  strength,  affording  the  smallest  possible  tar- 
get, the  inconspicuousness  of  which  may  be  further 
increased  by  the  use  of  artificial  means  as  will  be  later 
considered. 

The  forms  of  simple  rifle  trenches  shown  may  be 
regarded  as  normal  types  of  hasty  trenches  applica- 
ble to  passing  tactical  needs,  and  capable  of  being 
constructed  by  the  infantry  with  their  portable  tools 
in  a  comparatively  short  time. 

The  main  defect  of  the  simple  rifle  trench  is  its 
total  lack  of  lateral  communication,  rendering  diffi- 
cult the  reinforcing  of  the  fire  line  and  the  removal  of 
the  wounded.  If  it  be  likely  that  such  a  trench  may 
be  held  for  some  length  of  time,  it  will  pay  to  improve 
its  profile  in  the  manner  shown  in  Fig.  5,  Plate  I. 
This  profile  affords  a  covered  lateral  communication 
without  interfering  with  the  delivery  of  fire,  and  also 
a  more  convenient  cover  against  shrapnel  for  men 
sitting  on  the  step  with  their  backs  against  the  par- 
apet. 

The  types  of  profiles  shown  in  the  Figs.  1-5  rep- 
resent the  practical  limit  of  trenches  applicable  to 
hasty  works  for  use  on  the '  battlefield.  In  ordinary 
soils  their  construction  can  be  effected  in  four  hours 
or  less.  Still  stronger  profiles  may  be  constructed  by 
widening  and  deepening  the  excavation  and  by  in- 
increasing  the  thickness  of  the  parapet,  giving  bet- 
ter cover  to  the  riflemen  when  not  actually  manning 


—19— 

the  parapet,  as  well  as  resistance  to  the  penetration 
of  the  projectiles  of  field  and  heavier  guns. 

A  type  of  profile  secure  against  the  penetration 
of  light  field  artillery  projectiles  is  shown  in  Fig.  6, 
Plate  I.  Profiles  of  this  type  are  too  monumental 
and  require  too  much  work  to  be  applicable  to  hasty 
field  entrenchments.  They  belong  rather  to  the  type 
of  provisional  fortications  and  would  be  employed 
for  strategic  rather  than  tactical  purposes.  Their 
construction  is  the  business  of  technical,  rather  than 
non-technical  troops,  although  situations  may  arise  in 
which  hasty  field  works  way  be  developed  until  they 
reach  the  dimensions  of  the  stronger  types.  The  for- 
tified lines  of  position  on  the  Shahoand  at  Mukden  on 
both  the  Russian  and  Japanese  sides  afford  examples 
of  such  strengthening  of  hasty  field  works.  Figs.  7 
and  8,  Plate  P,  show  some  of  the  profiles  of  strength- 
ened trenches  employed  by  the  Russians  and  Japanese 
in  the  Manchurian  campaign. 

With  regard  to  the  location  of  rifle  trenches  with 
respect  to  the  foreground,  it  is  to  be  observed  that  in 
order  to  realize  the  full  effect  of  the  modern  firearms 
a  clear  field  of  fire  to  the  effective  range  of  the  wea- 
pons is  extremely  desirable.  The  experinces  of  the 
recent  campaign  in  Manchuria  have  shown  that  sen- 
sible losses  from  infantry  fire  were  incurred  at  dis- 
tances as  great  as  2,000  yards  and  that  at  1,000  yards 
this  fire  attained  a  tremendous  power.  But  in  order 
to  fire  effectively  at  the  longer  ranges  the  rifleman 
must  have  a  clear  view  of  the  foreground.  In  per- 
fectly flat  terrain,  whether  level  or  sloping,  the  com- 
mand afforded  by  the  usual  type  of  fire  trenches  is 
insufficient  to  afford  a  good  distant  view  of  targets  so 
insignificant  as  those  afforded  by  a  skirmish  line. 

If  it  were  merely  a  question  of  obtaining  a  good 
distant  view  the  best  location  for  fire  trenches  would 
unquestionably  be  on  the  military  crests  of  heights 


20— 

with  rather  steep  slopes,  but  such  a  location  involves 
two  disadvantages,  first,  the  sacrifice  of  grazing  fire 
which  is  so  much  more  effective  than  plunging  fire, 
and,  secondly,  exposure  of  the  trenches  to  the  ene- 
my's view.  If  the  slopes  of  the  heights  are  too  abrupt, 
there  is  the  further  danger  of  dead  space  at  the  shorter 
ranges. 

.  Fire  trenches  located  on  prominent  crests  are 
on  the  whole  disadvantageous,  affording  good  targets 
to' hostile  artillery  which  will  thereby  be  able  to  sup- 
port the  advance  of  the  hostile  infantry  with  good 
effect.  Examples  of  the  bad  effects  of  locating  rifle 
trenches  on  prominent  crests  are  furnished  by  the 
Russian  works  in  Manchuria  as  well  as  by  the  earlier 
trenches  of  the  Boers  in  South  Africa. 

To  secure  the  advantages  of  a  good  view  and  at 
the  same  time  to  minimize  the  exposure  of  the 
trenches,  a  location  on  gently  rising  ground  having 
a  concave  slope  is  unquestionably  the  best.  Unfortu- 
nately the  terrain  must  be  taken  as  we  find  it,  and 
ideal  positions,  such  as  that  of  the  French  at  St. 
Privat  with  its  gently  sloping  glacis-like  foreground, 
are  not  generally  afforded. 

The  location  of  the  fire  trenches  then  resolves 
itself  into  a  choice  between  the  military  crest  of  ris- 
ing ground  or  some  position  further  forward.  The 
disadvantages  of  a  conspicuous  location  on  the  crest 
have  already  been  pointed  out,  and  such  locations  are 
inadvisable  unless  the  trenches  be  so  strongly  con- 
structed that  they  can  withstand  ordinary  artillery 
fire,  such  as  the  Russian  trenches  on  203  Meter  hill. 
Positions  forward  of  the  crest  sacrifice  command  and 
limit  distant  view,  but  are  less  exposed  to  hostile  fire. 
The  chief  disadvantage  of  a  position  forward  of  the 
crest  is  the  difficulty  of  communicating  with  the  fire 
trenches,  either  for  reinforcing  the  same  or  for  with- 


drawing.  Such  being  the  conflicting  considerations, 
it  is  manifest  that  the  location  of  rifle  trenches  with 
respect  to  the  foreground  must  be  a  matter  of  com- 
promise, to  be  determined  by  sound  judgment  on  the 
part  of  officers  responsible  for  the  location. 

In  order  to  avoid  the  neutralizing  effect  of  hostile 
shrapnel  fire,  some  French  authorities  have  advocated 
the  abandonment  of  positions  on  or  in  advance  of 
crests  altogether  and  placing  them  on  the  counter- 
slopes  of  elevated  ground  on  or  near  the  rear  edges  of 
plateaus.  If  the  field  of  fire  be  not  too  restricted 
such  locations  may  occasionally  afford  marked  advan- 
tages. The  Boer  position  on  Spion-kop  was  of  this 
character.  Ordinarily,  positions  on  the  counter- 
slope  afford  a  relatively  short  field  of  fire,  permit  the 
enemy  to  approach  the  covering  crest  with  little  loss, 
and  to  take  up  a  covered  position,  at  short  ranges,  for 
a  further  advance.  In  general,  counterslope  positions 
have  little  to  recommend  them,  and  the  location  of 
fire  trenches  will  be  on  or  in  front  of  the  military 
crest,  so  as  to  secure  the  best  view  of  the  foreground 
consistent  with  a  reasonable  amount  of  security  from 
hostile  artillery  fire. 

In  rolling  country,  affording  a  succession  of 
crests  within  rifle  range  of  each  other,  it  will  often 
be  difficult  for  the  hostile  artillery  to  bring  a  well 
regulated  fire  to  bear  upon  the  trenches.  If  a  posi- 
tion for  direct  fire  be  taken  upon  the  nearest  crest  in 
front,  the  hostile  artillery  will  itself  be  exposed  to  in- 
fantry fire  from  the  trenches.  If  it  seeks  a  defiladed 
position  behind  the  crest,  it  may  not  be  able  to  fire 
at  angles  of  elevation  sufficiently  low  to  reach  the 
trenches. 

Besides  the  advantage  of  a  better  field  of  view  and 
of  fire  afforded  by  occupation  of  high  ground  the  ad- 
ditional advantages  follow: 


—22— 

(a)  The  crests  will  conceal  our  dispositions  in 
depth  from  the  enemy's  view. 

(b)  The  enemy's  assault  will  be  made  more  ex- 
hausting by  compelling  him  to  ascend  the  slopes. 

(c)  Good  facilities  will  be  afforded  for  launch- 
ing a  counter  attack. 

(d)  The  possibility  of  providing  several  tiers  of 
fire,  will  sometimes  be  offered. 

In  locating  a  trench  upon  a  crest  care  must  be 
taken  that  the  trench  be  not  outlined  against  a  sky- 
line. To  avoid  this  it  will  be  necessary  at  times  to 
push  the  trench  some  distance  down  the  forward 
slope.  If  the  forward  slope  is  convex  in  profile  or 
consists  of  a  succesion  of  crests,  it  will  sometimes  be 
necessary  to  advance  the  trenches  well  forward  in 
order  to  secure  the  best  field  of  fire. 

Fig.  9,  Plate  la  ,  shows  the  usual  location  of  a 
trench  on  or  near  the  crest  of  gently  rising  ground. 
Fig.  10,  Plate  la  ,  shows  a  location  on  the  forward 
slope.  The  best  location  must  be  decided  in  each  case 
on  the  ground  itself  by  placing  the  eye  at  the  eleva- 
tion of  the  parapet  and  sighting  over  the  foreground. 

When  trenches  have  to  be  located  upon  steep 
slopes  some  modifications  of  the  profile  are  neces- 
sarily involved.  To  enable  the  rifleman  to  fire  down 
hill  conveniently  the  relief  of  the  parapet  should  be 
less  than  in  the  normal  case,  as  shown  in  Fig.  11, 
Plate  la  .  The  diminished  relief  does  not  neces- 
sarily imply  a  decrease  of  cover,  for  if  the  enemy 
must  look  up  the  hill,  the  plane  of  defilade  will  rise 
towards  the  trench  and  a  less  height  of  cover  will 
serve  to  protect  men  in  the  trench. 

It  has  also  been  recommended  to  make  the  inter- 
ior slopes  less  steep  when  firing  down  hill  in  order 
to  avoid  a  weak  angle  at  the  interior  crest.  This  is 
of  doubtful  utility  for  it  involves  more  exposure  to 
shrapnel  fire. 


—23  — 

Since  trenches  on  crests  and  commanding  slopes 
are  more  exposed  to  the  enemy's  view  and  fire, 
especial  pains  should  be  taken  to  secure  concealment. 
This  may  be  partly  accomplished  by  locating  the 
trench  so  as  to  take  advantage  of  any  existing  natur- 
al screen  or  by  artificial  means  such  as  covering  the 
excavated  earth  with  grass,  sods,  weeds  or  placing 
branches  and  twigs  in  its  front.  The  short  lengths 
of  rifle  trenches  and  their  dispersion  along  the  slopes, 
both  in  depth  and  laterally,  contribute  to  conceal  the 
works  and  to  minimize  the  effect  of  hostile  artillery 
fire. 


I. 


Simple    S "handing  Trench 


Fig.  I 

• 

Simple  Standing  Trencfi,l'5  Command 


Simple  Standing  Trench  ,  Parapet  Suppressed 

V^^W/=4vV^|l^  ,  wxm^'tf^'^!^^— 

-  ^\\  ii.l-1'n 


Simple  Standing  Trench,  Rockj  Ground 
Fi_g.  ^ 


Completed     Standinq    Trench 

r~3.'~r-3.'~r--3'-i    " 


w^K^^^^^2^4wA  - ' "-?-  -  ^A\\4w/-J 
_J;Foothoia 

-3'5>^-  tt?-&~To    be   wasted 
-5'1 


Trianquiar  Profile   To   Resis~r    Pield    Guns 


la. 


Strengthened  Russian  TVench,Liaouanq 


Sod  Revet-men 


Strengthened  Japanese    Trench,  Chinchiatun 


Location  of  Trench  on  Military  Crest 


Military  Crest 


Location  of  Trench  forward  of  Military   Crest 

Military  Crest 


19  10 


Modified    Relief  On  Steep    Slopes 


Chapter     II 

PRINCIPLES  OF  THE  DEFENSIVE  ORGANIZATION. — SUPPORT- 
ING POINTS.— ARTILLERY  POSITIONS.— USE  OF 
ENGINEER  TROOPS. 

TN  taking  up  a  position  the  intentions  of  the  com- 
mander and  the  nature  of  the  terrain  govern. 
The  location,  choice  and  organization  of  the  position 
are  especially  influenced  by  the  object  of  the  combat, 
that  is,  whether  it  is  planned  to  make  a  purely  pas- 
sive defense  for  the  purpose  of  gaining  time  or  to 
seek  a  decisive  action  implying  offensive  conduct. 

The  general  location  of  a  position  is  influenced 
mainly  by  the  strategical  situation.  It  must  lie  fav- 
orably, not  only  to  the  direction  of  the  enemy's  line 
of  march  but  also  to  ones  own.  In  general  it  must 
be  the  natural  result  of  the  forward  march  without 
requiring  extensive  displacements  of  the  troops. 

The  choice  of  the  actual  position  results  from  the 
tactical  situation  in  connection  with  the  utilization  of 
the  advantages  of  the  terrain,  therefore  tactical 
strength  and  security  are  sought.  A  position  has 
value  only  when  it  compels  the  enemy  to  attack  or 
when  it  permits  the  defense  to  gain  the  desired  time, 
or  favorable  opportunities  for  his  own  offensive 
action  in  case  the  enemy  undertakes  a  turning  move- 
ment. 

As  the  opposing  forces  become  smaller  the  value 
of  organized  defensive  lines  diminishes,  since  the  at- 
tack can  readily  maneuver  the  defense  out  of  its  po- 
sition without  great  loss  of  time.  In  considering  the 
defensive  organization  of  lines,  therefore,  only  fronts 
of  some  extent  are  in  question— at  least  that  of  a 
brigade— which  cannot  be  turned  without  the  sacri- 

26 


—27— 

fice  of  considerable  time,  or  without  the  incurrence  of 
certain  risks.  Defense  of  a  defile  might  involve  a 
very  limited  length  of  line,  but  this  is  a  special  case. 

In  choosing  a  position  the  principal  require- 
ments to  be  satisfied  are:  a  wide  and  clear  field  of 
fire;  concealment;  freedom  of  maneuver  along,  and 
in  rear  of  the  position;  and  security  for  the  flanks. 
The  extent  of  the  position  in  frontage  and  depth  must 
also  be  suited  to  the  strength  of  the  forces  available 
for  its  occupation.  Too  extended  a  front  may  lead 
to  a  position  being  easily  pierced  but  may  be  justified; 
in  order  to  gain  secure  points  of  support  for  the 
flanks;  to  deceive  the  enemy  regarding  the  strength 
of  the  forces;  and  when  there  is  an  abundant  am- 
munition supply.  Too  limited  a  depth  increases  the 
difficulty  of  covering  the  supports  and  reserves  and 
their  lateral  movement.  It  may  therefore  lead  to  the 
disadvantageous  occupation  of  advanced  positions. 
Too  restricted  a  front,  implying  excessive  depth,  will 
facilitate  turning  movements  by  the  enemy  and  de- 
lay reenforcing  the  front  line. 

The  increase  in  size  of  armies  as  well  as  the 
marked  increase  in  fire  effect  of  modern  weapons 
and  the  more  liberal  equipment  of  intrenching  tools, 
have  all  conduced  to  an  extension  of  fronts  since 
1870.  The  French  position  at  Gravelotte  was  occu- 
pied at  the  rate  of  about  ten  men  per  yard  of  front 
and  similar  densities  obtained  at  Worth,  Mars  la 
Tour  and  Sedan.  The  German  lines  of  investment 
around  Paris  and  Metz  were,  however,  much  less 
strongly  occupied,  counting  but  three  to  four  men 
per  yard  of  front.  At  Plevna,  the  Turkish  position 
had  a  front  of  about  25  miles  and  was  held  with  only 
one  and  one  half  men  per  yard.  In  the  South  Afri- 
can war  the  Boers  held  their  positions  on  the  Tugela, 
11  miles  long,  with  some  7,000  men. 


—28- 

At  Mukden  the  Russian  position  was  something 
like  55  miles  front  and  was  occupied  by  a  little  more 
than  three  men  to  a  yard. 

It  must  be  evident  that  no  definite  rules  can  be 
formulated  for  the  necessary  strength  of  occupation 
of  a  position,  based  either  on  experience  or  reasoning. 
So  much  depends  upon  the  special  circumstances, 
such  as  the  terrain,  strength  of  works,  armament, 
and  quality  of  troops  that  any  figures  are  apt  to  be 
misleading. 

It  may,  however,  be  safely  assumed  that,  given 
good  troops,  a  good  field  of  fire,  and  cover,  a  strength 
of  one  and  one  half  men  per  yard  can  hold  a  position 
for  a  reasonable  length  of  time  against  greatly  super- 
ior forces,  but  the  defense  will  be  purely  passive. 

As  regards  the  organization  of  the  position  in  its 
details,  it  is  to  be  noted  that  there  must  be  an  inti- 
mate cooperation  between  the  working  of  the  infantry 
and  the  artillery.  Before  the  perfection  of  indirect  fire 
methods  the  number  of  artillery  positions  was  very 
limited  and  the  entire  organization  was  based  upon 
these  as  a  framework.  At  the  present  time  no  such 
limitation  as  to  artillery  positions  exists,  and  the  or- 
ganization is  based  upon  the  best  disposition  of  the 
infantry  trenches,  to  which  the  artillery  conforms. 

The  positions  for  the  field  artillery  should  be  so 
selected  as  to  enable  it:  to  combine  its  fire  with  that 
of  the  infantry  upon  the  probable  directions  of  attack 
up  to  the  decisive  moment;  to  combat  the  hostile 
artillery  up  to  the  nearest  positions;  and  to  meet 
possible  flank  attacks.  The  heavy  artillery  will  be 
posted  in  support  of  the  field  artillery  at  points 
where  it  can  bring  its  fire  to  bear  upon  presumed 
lines  of  march  and  artillery  positions  of  the  enemy. 
This  applies  especially  to  heavy  guns,  like  the  4.7- 
inch  rifle  whose  great  range  and  terrific  shrapnel 
effect  are  useful  against  the  enemy's  reserves  and 


—29— 

combat  trains.  Heavy  howitzers,  like  the  6-inch, 
are  best  held  in  a  position  of  readiness  near  good 
roads  until  the  direction  of  the  enemy's  main  attack 
is  developed. 

Owing  to  the  uncertainty  as  to  the  direction  of 
the  enemy's  main  attack,  the  artillery  positions  will 
necessarily  call  for  a  certain  amount  of  dispersion, 
but  as  a  rule  the  guns  will  be  grouped  by  battalions 
or  regiments  in  partial  or  completely  defiladed  gun 
epaulments.  The  infantry  positions  should  ordinar- 
ily be  so  far  to  the  front  of  the  artillery  positions  as 
to  protect  the  latter  from  hostile  infantry  fire  as  well 
as  from  attacks  in  flank  or  rear,  while  at  the  same 
time  not  exposing  the  infantry  to  loss  from  prema- 
ture bursts.  A  distance  of  at  least  600  yards  is  de- 
sirable. In  addition,  the  infantry  position  must  af- 
ford a  good  fire  on  the  near  foreground,  and  where 
the  terrain  does  not  permit  of  a  frontal  fire  it  must 
be  replaced  or  supplemented  by  flanking  fire.  In 
broken  terrain  or  on  slopes  with  convex  profiles, 
flanking  fire  will  frequently  afford  the  only  means  of 
covering  the  near  foreground  of  a  position. 

Machine  guns  will  be  employed  in  carefully 
covered  emplacements  at  points  where  a  special  re- 
e'n force ment!§  °f the  infantry  fire  is  necessary,  such 
as  upon  small  portions  of  the  terrain  useful  to  the 
eneny,  on  the  flanks  of  infantry  units,  and  on  the 
wings  of  the  position. 

The  area  of  terrain  within  which  the  posi- 
tion may  be  chosen  are  fixed,  to  a  large  extent,  by 
the  tactical  situation.  The  nearer  the  enemy,  the 
less  the  field  for  selection;  and  when  contact  has 
once  been  established  and  the  fight  has  begun,  the 
side  electing  to  hold  its  ground  must  generally  halt 
where  it  finds  itself  and  strengthen  the. terrain  as 
best  it  can.  In  prepared  battlefield  positions  where 
as  much  as  a  day's  march  separates  the  combatants, 


-   30- 

the  side  electing  to  hold  its  ground  for  the  time 
being  will  have  more  latitude  in  the  choice  of  a  posi- 
tion. It  may  advance  or  retire  some  distance  to  hold 
a  stream,  valley,  ridge  of  heights,  edge  of  plateau; 
or  to  take  advantage  of  any  other  favorable  topo- 
graphical features. 

The  details  of  the  "defensive  organizations  de- 
pend upon  the  intentions  of  the  commander,  to  which 
this  organization  must  respond.  Does  he  intend  to 
seek  a  decisive  action  by  an  immediate  and  vigorous 
attack?  If  so,  it  is  evident  that  there  is  no  use,  a 
priori,  for  defensive  works  on  the  particular  portions 
of  the  front  covered  by  the  attacking  troops.  In 
such  case,  defensive  organizations  will  be  under- 
taken only  on  such  parts  of  the  line  as  are  not  for 
the  time  being  involved  in  the  attack.  During  the 
progress  of  the  attack,  many  occasions  will  arise, 
especially  in  the  long  drawn-out  battles  of  today, 
calling  for  the  employment  of  defensive  works  for 
temporary  purposes  with  a  view  to  facilitating  fur- 
ther progress,  holding  captured  points,  etc. ;  but  the 
need  for  these  cannot  be  foreseen,  and  their  use  is 
dependent  upon  the  course  cf  the  fight. 

Does  the  commander  intend  to  receive  the  attack 
of  the  enemy  on  a  position  of  his  own  choosing,  with 
a  view  to  wearing  him  out  and  making  him  disclose 
his  intentions,  in  order  then  to  pass  to  a  resolute  and 
determined  attack?  If  so,  the  original  defensive 
organization  must  be  more  thoroughly  planned  and 
executed  than  in  the  first  case.  At  the  same  time 
care  must  be  exercised  not  to  resort  to  such  excessive 
strengthening  of  the  position  as  may  influence  the 
enemy  not  to  attack.  For  this  will  defeat  the  inten- 
tions of  the  commander  and  injure  the  morale  of  the 
troops  who,  experience  has  shown,  are  loth  to  quit 
elaborate  fortifications  constructed  at  the  expense  of 


—31— 

much  time  and  labor  and  affording  them  excellent 
cover. 

Does  the  commander  seek  merely  to  hold  his 
ground  — in  other  words,  to  make  a  passive  defense 
for  the  purpose  of  gaining  time?  Then  his  defensive 
organization  must  be  still  more  comprehensive  and 
elaborate  and  limited  only  by  the  time  and  resources 
available.  Of  this  character  were  the  several  forti- 
fied positions  of  the  Russians  in  Manchuria,  which, 
while  fulfilling  their  object  so  far  as  frontal  attacks 
were  concerned,  nevertheless  failed  because  their 
flanks  were  turned. 

But  whatever  the  object  to  be  served  by  the 
defensive  organization  of  lines,  the  same  general 
principles  are  applicable.  These  principles  may  be 
summarized  as  follows: 

1.  The  defensive  position  must  have  sufficient 
depth. 

2.  The  defensive  line  is  discontinuous  laterally. 
The  defensive  organization  in  depth  is  merely 

the  adaptation  of  defensive  measures  to  tactical  for- 
mations. The  attack  will  be  made  as  a  succession 
of  efforts  or  impulses  to  which  the  defense  will  re- 
spond by  a  succession  of  resistances.  The  succession 
of  resistances  may  take  the  form  of  a  series  of  suc- 
cessive prepared  lines,  each  offering  resistance  in 
turn,  or  a  single  prepared  line  of  resistance  succes- 
sively strengthened  from  the  rear  by  the  bringing 
up  of  the  supports  and  reserves.  The  former 
method  is  represented  by  the  French  school  of  thought 
with  its  advanced  posts,  advanced  combat  line,  main 
line  and  second  line  (position  de  repli)  while  the  sec- 
ond method  is  represented  by  the  German  school  of 
thought. 

The  method  of  successive  prepared  lines  of  re- 
sistance, while  theoretically  sound,  is  open  to  the 


-32— 

objection  that  troops  will  not  hold  so  long  nor  so  well 
if  they  know  that  there  are  in  rear,  other  prepared 
defensive  lines.  This  view  of  the  effect  of  succes- 
sive fortified  lines  is  supported  by  the  results  of  the 
Manchurian  campaign  in  which  the  Russians  fre- 
quently offered  but  feeble  resistance  from  their  ad- 
vanced lines.  This  yielding  and  falling  back  of  the 
foremost  lines  is  injurious  to  the  morale  of  the  de- 
fense as  a  whole. 

The  concentration  of  all  defensive  measures  on 
a  single  prepared  line,  relying  upon  mobile  supports 
and  reserves  for  the  necessary  organization  in  depth, 
is  more  conducive  to  the  best  morale  of  the  troops 
and  more  in  keeping  with  the  maintenance  of  the 
offensive  spirit.  It  is,  therefore,  on  the  whole,  con- 
sidered preferable. 

The  principle  of  the  lateral  discontinuity  of  the 
defensive  organization  is  in  compliance  with  the 
principle  of  the  economy  of  forces,  is  better  adapted 
to  the  tactical  handling  of  organized  units,  and  takes 
advantage  of  the  long  range  of  modern  weapons. 
Its  practical  result  is  that  the  defensive  organiza- 
tions are  grouped  at  certain  points  along  the  front, 
leaving  intervals  of  greater  or  less  extent  which  are 
defended  by  the  cross  and  flanking  fire  of  adjacent 
organized  points,  as  well  as  by  the  play  of  their  sup- 
ports and  reserves.  The  interval  between  successive 
organized  points  is  dependent  upon  the  topographical 
features  of  the  terrain  and  the  necessity  for  recip- 
rocal flanking  fire,  which  limits  this  interval  to  800 
or  1,000  yards. 

Such  organized  defensive  points  located  along 
the  front  of  a  prepared  position  are  called  support- 
ing points.  Formerly  it  was  deemed  necessary  that 
closed  works,  in  the  nature  of  forts  or  redoubts, 
should  constitute  the  organization  of  supporting 
points;  and  this  to  a  certain  extent  still  obtains  in 


-33- 

the  case  of  permanent  fortifications  and  provisional 
works.  The  underlying  idea  of  closed  works  is  that, 
by  virtue  of  their  all  round  defense,  they  will  be 
capable  of  maintaining  themselves  after  the  line  is 
pierced  and  thus  afford  opportunity  for  the  defense 
to  reestablish  itself.  In  field  fortifications,  especialy 
in  hasty  works  for  use  on  the  battlefield,  closed  works 
find  little  or  no  application.  Such  works  are  difficult 
to  conceal,  and,  unless  very  strongly  organized  with 
bomb-proof  shelters  and  interior  communications  (for 
which  time  is  ordinarily  lacking  in  field  fortifications), 
they  will  become  veritable  shell  traps,  liable  to  sub- 
ject their  garrison  to  annihilation  by  artillery  fire. 
To  secure  the  fullest  development  of  fire  effect  from 
modern  weapons  there  is  required  a  wide  extent  of 
trenches  rather  than  the  limited  faces  of  closed  works. 
All  the  objects  formerly  sought  by  the  use  of  the 
old  types  of  closed  works,  with  their  massive  profile 
and  geometrical  trace,  can  be  better  realized  by  a 
proper  grouping  of  simple  rifle  trenches,  either  alone 
or  in  conjunction  with  some  existing  natural  or  arti- 
ficial feature,  such  as  a  village,  group  of  buildings, 
or  a  clump  of  woods.  If  deemed  necessary,  such 
trenches  can  be  so  laid  out,  that,  although  discontin- 
uous, they  can  bring  fire  in  any  and  all  directions; 
be  entirely  surrounded  by  obstacles;  and,  in  connec- 
tion with  dispersed  covers,  perform  all  the  functions 
of  a  closed  work  with  far  better  concealment,  better 
protection  and  infinitely  less  labor.  In  the  rare  cases 
where  a  closed  work  may  be  used,  such  as  a  support 
for  a  wing  or  behind  or  in  a  specially  weak  or  dan- 
gerous portion  of  the  front,  it  will  ordinarily  take  the 
form  of  a  simple  ring  trench  enclosed  by  a  continuous 
line  of  obstacles  and  will  have  a  fixed  garrison  assigned 
to  it.  Fig.  2,  Plate  II,  shows  a  form  of  ring  trench 
with  overhead  cover  as  recommended  for  the  German 
service. 


-34  - 

Closed  works  of  the  character  used  by  the  Rus- 
sians in  their  positions  at  Liaoyang  and  Mukden, 
although  field  fortifications,  belong  rather  to  the  class 
of  provisional  fortifications  and  may  find  application 
under  similar  situations,  that  is,  where  there  is  abun- 
dant time  and  the  works  can  be  constructed  with  the 
assistance  of  civilian  labor.  But  even  here  the  same 
results  can  be  obtained  by  the  proper  combination  of 
rifle  trenches,  obstacles,  covers,  communications  and 
their  accessories.  Fig.  1,  Plate  II,  shows  one  of  the 
Russian  redoubts  at  Liaoyang,  while  Plate  III  shows 
a  form  of  Japanese  redoubt.  The  latter,  approximat- 
ing a  ring  trench  in  the  simplicity  and  ease  of  its  con- 
struction, is  a  decidedly  better  form  for  field  fortifica- 
tion than  the  former. 

The  term  supporting  point,  as  now  understood, 
refers  to  an  area  of  ground  organized  defensively  for 
a  definite  object  by  the  troops  themselves  with  the 
means  usually  available.  Only  very  exceptionally 
will  it  present  a  closed  form  with  a  continuous  fire 
line  and  then  generally  only  in  the  shape  of  a  ring 
trench.  Except  for  permanent  and  provisional  works, 
supporting  points  in  the  nature  of  forts  and  redoubts 
of  monumental  construction  will  find  no  application. 
In  Fig.  1,  Plate  IV,  is  shown  the  general  layout  of 
the  Russian  works  on  203  Metre  hill,  the  whole  pre- 
senting an  excellent  example  of  a  group  of  trenches 
constituting  a  strong  supporting  point.  Fig.  2,  Plate 
IV,  shows  the  supporting  point  on  Redoubt  hill,  apart 
of  the  outer  Russian  line  at  Liaoyang. 

A  prepared  fortified  line  of  resistance  will,  there- 
fore, consist  normally  of  a  line  of  supporting  points, 
the  intervals  being  such  that  mutual  defense  by  cross 
and  flanking  fires  is  assured.  The  supporting  points 
themselves  may  be  natural  topographical  or  existing 
artificial  features  (villages,  woods,  etc.)  organized 
defensively,  groups  of  rifle  trenches,  or  combinations. 


—35— 

Each  supporting  point  will  be  organized  and  defended 
by  a  tactical  unit.  The  principle  of  discontinuity  is 
not  limited  merely  to  the  intervals  between  successive 
supporting  points.  In  extended  battlefield  positions 
still  larger  intervals  may  be  left  between  the  larger 
tactical  units,  such  as  divisions  and  army  corps,  the 
object  being  to  tempt  the  enemy  to  make  an  attack 
upon  the  interval  and  thus  to  expose  himself  to 
counter  attacks  behind  the  line.  In  the  Russian  outer 
line  at  Liaoyang  there  was  an  interval  of  one  and  one 
half  miles  between  the  positions  of  the  I  and  III  Sibe- 
rian Corps,  which  the  Japanese,  however,  refrained 
from  attacking. 

The  flanks  of  a  position  will  always  be  tempting 
points  for  the  enemy's  attacks,  and  should  therefore 
be  secured  by  resting  them  on  impassable  obstacles, 
or  if  this  cannot  be  done,  by  echeloning  them  to  the 
rear  and  keeping  strong  reserves  close  at  hand. 

Long  trenches  are  not  desirable,  even  where  the 
ground  permits  of  their  application,  which  it  ordinar- 
ily does  not.  Any  part  of  a  long  trench  once  found 
by  the  enemy  easily  leads  to  the  disclosure  of  the  re- 
mainder. A  long  trench  penetrated  at  any  point  will 
generally  become  untenable.  For  these  reasons  it  is 
considered  preferable  to  limit  the  length  of  single 
trenches  to  that  required  for  a  company  and  if  a 
greater  development  of  fire  is  needed,  additional 
trenches  of  company,  platoon*  or  even  squad  length 
may  be  constructed.  The  several  trenches  of  a  group 
need  not,  and  generally  would  not  be  on  one  line,  but 
might  be  separated  in  depth  as  well  as  laterally.  By 
this  dispersion  of  works  a  certain  flexibility  is  ob- 
tained, permitting  the  best  adaptation  to  the  ground 
and  lending  itself  to  concealment  and  protection. 

The  size  of  the  tactical  unit  assigned  to  a  sup- 
porting point  depends  upon  the  tactical  importance 
of  the  supporting  point  and  upon  the  intervals  sep- 


arating  it  from  the  adjacent  supporting  points.  A 
battalion  forms  a  very  convenient  tactical  unit  and 
will  be  most  often  used.  A  portion  of  the  battalion 
will  be  employed  in  the  firing  line  and  the  remaining 
portion  as  a  support  to  reenforce  the  firing  line. 

For  the  conduct  of  the  combat  and  to  fix  respon- 
sibility, the  entire  defensive  front,  if  of  any  extent, 
will  be  divided  into  sectors,  to  each  of  which  will  be 
assigned  a  complete  tactical  unit.  The  division  into 
sectors  is  influenced  by  the  topography,  the  strength 
of  the  forces,  and  the  intentions  of  the  commander. 
With  a  large  force  the  initial  division  into  sectors  will 
be  made  by  the  commander-in-chief,  who  will  assign 
the  larger  tactical  units,  such  as  field  armies  or  divi- 
sions, to  definite  portions  of  the  front  and  give  to  each 
its  mission.  The  larger  sectors  are  further  subdivided 
into  smaller  sectors  by  the  commanders  of  larger  units 
down  to  brigades  and  even  regiments.  By  this  means 
responsibility  is  fixed  and  the  exercise  of  command 
simplified. 

Each  sector,  large  and  small,  will  ordinarily  have 
a  sector  reserve  at  the  diposal  of  the  commander  of 
the  sector.  The  strength  of  this  reserve  will  depend 
upon  the  tactical  object  in  view.  Where  it  is  merely 
a  question  of  holding  ground  the  reserves  will  not  be 
so  strong  as  where  a  decisive  issue  is  sought.  In  ex- 
tended battlefields,  portions  of  the  front  will  be  or- 
ganized with  a  view  to  offensive  action,  and  the 
strength  and  location  of  the  reserves  will  be  governed 
accordingly. 

The  practical  method  of  organizing  a  defensive 
line  depends  upon  the  time  available  and  requires 
the  cooperation  of  all  the  arms  of  the  service,  in- 
cluding the  technical  troops.  It  will  manifestly  be 
impracticable  for  the  commander-in-chief  of  a  large 
force— say  several  field  armies— to  inspect  personally 
the  entire  front  and  to  decide  upon  the  details  of  the 


—37  — 

position  and  of  the  works  to  be  constructed.  Only 
general  directions,  based  upon  the  map  and  upon  the 
military  situation  can  be  given  by  the  commander  of 
a  large  force.  These  directions  will  merely  specify 
the  fronts  to  be  occupied  by  the  larger  units,  their 
mission  and  designate  the  general  reserves  and  their 
location. 

Ordinarily  the  time  available  will  permit  no 
higher  than  division  commanders  to  make  a  recon- 
naisance  (either  in  person  or  by  a  designated  staff 
officer)  upon  which  to  base  the  details  of  a  defensive 
line.  When  such  reconnaissance  is  made  prior  to 
the  issue  of  orders  the  division  commander,  or  his 
delegated  staff  officer,  should  be  accompanied  by  the 
commander  of  the  artillery  and  engineers  for  the 
purpose  of  coordinating  the  work  of  the  latter  arms 
with  that  of  the  infantry.  Not  infrequently,  a  prior 
reconnaissance  by  the  division  commander  is  imprac- 
ticable and  it  is  then  possible  for  him  to  make  dispo- 
sitions of  a  general  character  only,  based  on  the  map 
and  the  general  situation,  leaving  to  brigade  and  reg- 
imental commanders  the  decision  as  to  details. 

The  necessity  for  a  good  understanding  of  the 
organization  of  defensive  positions  on  the  part  of  all 
line  officers  therefore  becomes  apparent.  Without 
such  uniformity  of  application,  the  use  of  field  works 
to  strengthen  the  terrain  will  produce  no  satisfactory 
results. 

Use     of     Engineers 

It  is  now  accepted  as  a  principle  that  all  hasty 
field  works  must  be  constructed  by  the  troops  who 
are  to  defend  them,  and  all  troops,  infantry,  artillery, 
and  cavalry  are  equipped  with  tools  for  this  purpose. 
The  need  for  hasty  works  under  present  day  con- 
ditions is  so  frequent  and  so  extensive  that  their 
construction  cannot  be  delegated,  as  was  formerly 


—38- 

the  case,  to  the  engineers  whose  numbers  will  be 
quite  inadequate  for  such  a  purpose.  There  are, 
however,  many  classes  of  works  required  in  the 
organization  of  a  position  which  demand  operations 
for  which  the  other  troops  are  neither  trained  nor 
equipped  and  which  can  be  best  carried  out  by  the 
technical  troops.  Of  this  character  are  the  following : 

(a)  Demolitions,  calling  for  the  use  of  high  ex- 
plosives in  clearing  the  foreground,  and  obstructing 
the  enemy's  communications. 

(b)  Cutting  down  of  heavy  timber,   for  which 
the  infantry  tools  are  not  adapted. 

(c)  Assisting  in  the   organization  of  specially 
important  supporting  points  involving  the  employ- 
ment of  artificial  obstacles  and  substantial  covers. 

(d)  Providing    communications,    especially 
bridges,  in  rear  of  and  along  the  position. 

(e)  Executing  special  constructions  such  as  ob- 
servation stations,  shelters  for  the  wounded. 

(f )  Constructing  works  on  the  second  line  of 
defense,  if  such  should  be  contemplated. 

In  general,  the  engineers  will  be  employed  on 
works  of  general  interest  not  definitely  assign- 
able to  any  other  combat  unit,  and  on  works  requir- 
ing special  technical  skill  and  tools. 

Since  the  proportion  of  engineers  is  small,  any 
attempt  to  apportion  them  uniformly  over  an  ex- 
tended front  must  lead  to  such  a  scattering  of  per- 
sonnel and  material  as  to  preclude  any  practical 
results.  Undue  subdivisions  will  render  supervision 
by  engineer  officers  impossible  and  will  complicate  the 
subsistence  and  administration  of  the  engineer  units. 
All  considerations,  therefore,  point  to  the  employ- 
ment of  the  engineers  in  tactical  units,  viz., 
companies. 

When  a  reconnaissance  precedes  the  actual  or- 
ganization of  a  position  the  senior  engineer  officer 


—39— 

will  be  able  to  furnish  advice  as  to  the  best  employ- 
ment of  the  engineer  troops  to  carry  out  the  inten- 
tions of  the  commander,  and  this  would  naturally  be 
followed  in  assigning  the  engineer  troops.  Where 
no  such  reconnaissance  can  be  made  the  assignment 
of  the  engineers  will  have  to  be  made  more  or  less 
arbitrarily  and  their  employment  decided  by  the 
commander  of  the  units  to  which  they  may  be 
attached.  There  being  three  pioneer  companies  to 
each  individual  battalion,  one  company  may  be  as- 
signed to  each  brigade  for  the  execution  of  any 
works  deemed  necessary  by  the  brigade  commanders. 
The  engineer  troops  are  auxiliaries  to  the  other 
combat  troops  and  can  render  valuable  services  in 
the  organization  of  defensive  positions  as  well  as  on 
the  offensive.  In  the  latter  case  they  will  accompany 
the  leading  troops  of  the  attack  equipped  with  demo- 
lition and  pioneer  tools  and  high  explosives,  prepared 
to  overcome  or  remove  any  obstacles  interfering  with 
the  advance  of  the  infantry,  and  to  assist  in  the 
organization  of  captured  points.  To  secure  the  best 
results  from  the  employment  of  engineer  troops  on 
the  battlefield  it  is  incumbent  that  all  combat  officers 
should  understand  their  functions,  capacity  for 
executing  work,  as  well  as  their  limitations. 


Plate  II 

SKetch     o~f    a    s~t"ronqlu      cons~f~ruc~f  ed     supporting 
Point"    "for    a    company     at"     vvar  s~hrenqth,    4^4-cov'ers 
for    220  men. 


Russian   Infan+rLj    Redoub~t"  at    Liaouanq 


Chevaux    de   frise....  xxw  Wire  en-fon^lemen+  ....  XXXX 

Mili  +  ary   Pits. °o°O  R -. Ramp 

M.M Machine  .gun  emplacement  j ,. 


Plaie 


JAPANESE      FIELD    REDOUBT 
NEAR    KAN@R  IENHSIEN. 


s 


PLAN.       Scale   <L_£S_2£_ZLJ2°  Feet 


Borr.b  Froof  s 

"Traverses 

l_  a-frines  L 

S  +  C'-e-room  M 

Corrmunica  +  mq  "Trenches  C 

F!o^K    De-fer.ses  F 


D     Cross  Sec+ion  Sec+ion    C~D 

Bombproo"f    in    Fron+    Parapet. 


Sec+icn  K-L.      Section  G-H 


Elevation.         Section  A-B. 
Flank     Defense. 

Scale     for   Sections      °       5      '°      15      go     25    Feef 

Nnfe  The    dash  and     dot      line     represents    fh*= 
original     ground     surface. 


Near  the  telephone  cabinet 
(marked  T)onthe  upper' 
road  were  small  bombprc 
and  dug  outs, and  a  local 
dressing  station 

DEFENSES  OF  203  METRE  HILL 


R  Right  Re  doubt 

L          Left  Redoubt 

Wire  Entanglements 
---  — -     Trenches  unoccupied 
.M_n_ri_     Traversed  trenches  occupied 
2-\iy-vi^L     Lower(circular)trench 
'•— I'lli'lr-1     Central  Battery  with 
,          L        connecting  trenches 
Trench  on  crest-line  with  communi- 
cation trench  to  upper  road 


X    X    Upper  rood 
Y  Y  Lower  road 
•      Commandant's 

bomb  proof 
T    Telephone  Cabinet 
fP]    Dressing  Station 
R    R  Ra v  i  ne  where  the 
reserves  were 
usally  kept 
*    *fbucjasses 


SUPPORTING  POINT  ON  REDOUBT  HILL, 
RUSSIAN  OUTER  LINE  AT  LIAOYANG 

A       A      Splinter   Propfs  Communicating  Trench 

Open  Cover  Trenches  (single  Parapet) 

Simple  Standing  Trench  ufwrnup.  Traversed  Fire  Trench 
Communicating  Trench      =O=Traversed  Comm  uni- 
Cdouble  Parapet)  eating   Trench  j.H 


B      B 


Chapter     III 

ACCESSORY  FEATURES  OF  RIFLE  TRENCHES.— HEAD  COVER, 
TRAVERSES,  SHELTERS,  OBSERVATION  STATIONS,  MA- 
CHINE  GUNS,   DRAINAGE,  WATER   SUPPLY, 
NIGHT   FIRING,  AMMUNITION  RE- 
CESSES, ETC.    < 

IN  the  usual  case,  time  for  the  organization  of 
hasty  battlefield  fortifications  will  be  very 
limited,  even  on  the  part  of  the  defense,  and  the 
chances  are  that  the  simple  standing  trench  will  have 
to  fulfill  all  requirements.  However,  it  would  be  a 
serious  mistake  on  the  part  of  any  commander  not  to 
endeavor,  in  the  time  at  his  disposal,  to  render  his 
hasty  fortifications  as  effective  as  possible.  There 
are  two  considerations  involved,  more  or  less  opposed, 
viz. : 

(a)  The  fortifications  should  be  made  as  effective 
as  possible,  but 

(b)  The   troops  must   not   be  so  exhausted  by 
excessive  work  as  to  seriously  impair  their  fighting 
power.  v. 

Fortunate  is  the  commander  who  possesses  the 
good  judgment  necessary  to  attain  the  happy  mean 
between  these  two  extremes. 

The  simple  standing  trench  having  been  con- 
structed, there  are  various  accessory  means  of  im- 
proving it.  If  it  is  evident  from  the  first  that  there 
will  be  ample  time,  these  accessory  features  should 
be  embodied  in  the  original  plan;  but,  in  the  normal 
case  this  will  not  be  practicable,  and  their  considera- 
tion must  be  deferred  until  after  a  usable  trench  has 
been  completed.  These  means  of  further  improve- 
ment will  now  be  discussed. 

43 


—44— 
Head     Cover 

Head  cover  is  obtained  by  either  notching 
or  loopholing  the  parapet.  The  simplest  manner 
of  doing  the  former  is  by  placing  small  heaps  of 
earth  on  the  parapet,  at  intervals  corresponding  to 
the  spacing  of  the  riflemen;  each  man  firing  to  the 
right  of  the  heap  immediately  in  his  front  (see  Fig. 
1,  Plate  V).  This  method  is  of  questionable  value  as 
the  man  does  not  get  much  protection  and,  at  short 
ranges,  the  enemy  is  offered  an  excellent  aiming 
point.  If  mud  or  sods  are  available,  the  sides  of  the 
mounds  can  be  made  steep  (see  Fig.  2,  Plate  V),  and 
the  protection  then  becomes  of  real  value.  Any 
available  material  may  be  made  use  of  to  sustain  the 
side  slopes  of  the  mounds  at  a  greater  angle  of  re- 
pose than  the  soil  of  which  they  are  composed  will 
naturally  take.  Notched  parapets  were  frequently 
used  by  both  Russians  and  Japanese  in  Manchuria. 

Various  forms  of  loophole  are  shown  in  Figs.  3 
to  9,  Plate  V.  Certain  terms  are  used  to  define  the 
various  parts  of  a  loophole,  viz. :  the  bottom  is  called 
the  floor  or  sole,  the  sides  are  called  the  cheeks  and 
the  narrow  portion  the  throat.  It  is  evident  that  the 
only  essential  difference  between  notches  and  loop- 
holes is  that  the  latter  has  a  roof;  therefore  the 
same  descriptive  terms  apply  to  the  notch.  Mater- 
ials for  loopholes  will  not  generally  be  available  for 
hasty  works,  but  they  should  be  employed  whenever 
practicable  as  they  materially  increase  the  cover  and 
contribute  to  greater  accuracy  in  shooting. 

The  throat  may  be  at  the  end  of  the  loophole  near- 
est to  the  rifleman,  in  which  case  he  gets  the  best 
use  of  his  rifle  but  not  such  good  protection;  or  it  may 
be  at  the  end  farthest  away  from  the  soldier,  in 
which  case  he  gets  maximum  protection  but  must 
move  about  a  pivot  in  order  to  change  his  aim;  or  the 


-45— 

throat  may  be  located  at  some  intermediate  point  as 
a  compromise.  Various  locations  are  indicated  in 
the  figures. 

The  Hopper  Loophole,  Fig.  5,  Plate  V,  is  a  most 
effective  form,  especially  if  the  throat  is  closed  by  a 
steel  plate  spiked  to  it.  The  plate  should  be  about 
one-half  inch  thick,  if  of  hard  steel,  and  is  pierced 
by  a  comparatively  small  opening  for  accomodating 
the  rifle.  Figures  6  and  7  show  the  forms  of  plates 
used  by  the  Japanese  and  Russians  in  the  late  war. 

If  the  material  composing  the  loophole,  or  notch, 
is  hard  and  resisting,  the  throat  should  always  be 
placed  to  the  front,  or  the  cheeks  in  front  of  the 
throat  should  be  stepped  to  prevent  glancing  in  of 
projectiles. 

Where  the  character  of  fire  to  be  delivered  in- 
volves a  wide  lateral  and  a  small  vertical  angle,  loop- 
holes may  take  the  forms  of  slits.  Such  a  form  will 
result  from  laying  logs,  or  fascines,  lengthwise  on 
the  parapet,  supported  at  intervals  by  sods  or  other 
material,  as  shown  in  Figs.  8  and  9,  Plate  V.  Various 
other  materials,  it  is  readily  seen,  may  be  used  in 
constructing  this  form  of  loophole. 

Head  cover  is  valuable  chiefly  for  neutralizing 
the  effect  of  hostile  shrapnel  fire,  thus  enabling  the 
riflemen  to  man  the  parapet  at  any  and  all  stages  of 
the  combat.  It,  however,  increases  the  visibility  of 
the  parapet  and  restricts  the  field  of  fire.  At  close 
range  the  notches  and  loopholes  serve  as  aiming 
points  to  steady  the  fire  of  the  enemy,  especially  if 
he  can  see  light  through  them  when  unoccupied.  In 
the  latter  case  he  waits  until  the  light  is  obscured 
and  then  fires,  knowing  he  has  an  animate  target. 
It  is  obvious  that  the  defense  must  provide  a  proper 
background  for  the  openings,  or  removable  screens. 
Simple  curtains  made  of  empty  sacks  or  sand  bags 
will  suffice. 


—46— 
Traverses 

An  unbroken,  continuous  trench  would  be  ex- 
posed to  enfilade  fire,  and  also  a  shell  or  shrapnel 
bursting  therein  would  have  wide-spread  effect. 
These  difficulties  are  partially  met  by  constructing 
the  trenches  in  short  lengths.  It  is,  however,  desir- 
able, if  time  permits,  to  further  subdivide  each  trench 
by  means  of  traverses,  the  interval  between  adjacent 
traverses  not  exceeding  eight  yards.  Better  defilade 
is  thus  secured,  the  material  effect  of  any  burst  is 
confined  to  very  narrow  limits,  and  the  moral  effect 
upon  the  defenders  of  observing  the  destruction 
wrought  by  a  successful  burst  is  practically  elimin- 
ated. 

The  traverses  should  be  about  one  yard  thick  at 
the  height  of  the  interior  crest.  While  their  efficiency 
for  defilade  is  a  direct  function  of  their  height,  it 
must  be  remembered  that  inconspicuousness  of  the 
trench  is  of  prime  importance.  It  is  therefore  inad- 
visable to  carry  them  much,  if  any,  above  the  general 
line  of  the  crest,  and  in  no  case  should  this  difference 
of  level  be  greater  than  18  inches. 

When  practicable,  provision  should  be  made  for 
the  traverses  in  the  initial  laying  out  of  the  trenches, 
failing  this  they  can  be  constructed  later.  Figures 
10  and  11,  Plate  V,  show  two  methods  of  traversing 
a  trench,  the  latter  being  considered  preferable  be- 
cause it  does  not  reduce  the  space  available  for 
occupancy  by  riflemen.  If  the  first  form  is  used,  the 
sides  of  the  traverse  should  be  made  as  steep  as  pos- 
sible, in  order  that  the  reduction  of  space  on  the 
firing  line  may  be  a  minimum.  Traverses  arranged 
as  in  Fig.  .10  are  called  "attached"  traverses  and 
those  arranged  as  in  Fig.  11,  '  'detached"  traverses. 

Shelters 

In  these  days  of  accurate  artillery  fire  it  is  essen- 


—  47  — 

tial  that,  if  the  trenches  are  to  be  occupied  for  any 
length  of  time,  some  sort  of  shelter  be  provided  for 
the  men  when  they  are  not  actually  manning  the 
parapet.  This  shelter  should  be  made  as  effective  as 
time,  materials,  and  the  fitness  of  the  troops  for  such 
work,  permit.  It  will  vary  from  the  simplest  form 
of  splinter-proof  to  shelter  proof  against  the  heaviest 
siege  artillery  projectile.  The  overhead  thickness  of 
material  for  shelter  will  vary;  6  to  8  inches  of  earth 
on  thin  boards  giving  protection  from  shrapnel  and 
splinters,  3  feet  of  earth  on  6  inches  of  timber  to 
resist  light  field  guns,  and  6  feet  of  earth  on  12 
inches  of  timber  being  the  least  that  will  afford  pro- 
tection when  the  fire  of  siege  guns  and  howitzers  is 
to  be  taken  into  account.. 

The  great  value  of  the  shelters  in  the  trench  is 
that  the  men  are  protected  in  a  position  from  which 
they  can,  in  time  of  need,  very  rapidly  man  the 
parapet. 

Various  forms  for  these  shelters  are  shown  in 
the  Figs.  12  to  18,  Plates  V  and  VI.  In  Figure  18, 
Plate  VI,  is  shown  a  combination  of  head  cover  and 
shelter  which  is  very  effective.  It  will  be  noted  that 
in  some  cases  the  shelter  is  closed  to  the  rear  by  a 
sort  of  trapdoor  or  cover  which,  while  not  heavy 
enough  to  be  unwieldy,  will  still  offer  considerable 
resistance  to  small  fragments  and  splinters.  Timber 
will  usually  be  the  material  used  to  sustain  the  roof, 
but  railroad  rails,  or  other  forms  of  steel  beams,  are 
equally  suitable. 

Time  being  available  for  their  construction,  pro- 
vision should  be  made  for  the  shelters  in  laying  out 
the  trench,  but  they  can  also  be  readily  constructed 
after  the  completion  of  the  excavation  of  the  trench, 
and  on  the  field  of  battle  this  will  be  the  usual  order 
of  procedure. 

In  determining  the  area  of  overhead  cover  to  be 


-48— 

provided,  allow  six  square  feet  per  man  for  tem- 
porary occupancy,,  and  twelve  square  feet  per  man 
if  the  occupation  is  to  be  of  long  duration. 

Observation     Stations 

Except  when  the  garrison  are  actually  required 
to  man  the  parapet,  they  will  all  be  under  cover  save 
a  few  lookouts  whose  duty  will  be  to  give  timely 
warning  of  the  movements  of  the  enemy.  These 
lookouts  must  be  able,  while  well  protected,  to 
thoroughly  observe  the  foreground.  In  the  normal 
case  there  will  be  trees,  or  some  artificial  construction 
already  existing,  which  may  be  made  of  use  as  a  point 
of  observation.  Such  facilities  do  not,  however, 
always  exist,  and  specially  constructed  observation 
stations  must  then  be  provided.  These  must  afford 
the  occupant  the  maximum  amount  of  cover  con- 
sistent with  his  being  able  to  efficiently  perform  his 
duty  as  lookout.  The  two  forms,  furnishing  basic 
idqas,  are  shown  in  Figs.  19,  Plate  Vl-a,  and  20, 
Plate  VI.  In  the  first  form  the  bottom  of  the  trench 
is  lowered  so  that  the  man  can  just  look  over  the 
superior  slope;  he  must  rely  upon  inconspicuous 
headgear  or  a  screen  to  shelter  his  head  from  view. 
In  the  second  form  he  is  given  overhead  cover. 

In  all  cases  observation  stations  must  be  so  lo- 
cated and  constructed  that  they  will  not  disclose  the 
location  of  the  trenches.  Where  it  is  practicable 
they  should  always  be  placed  in  the  trenches,  but 
there  will  be  many  cases  where  they  will  have  to  be 
located  in  advance  of  or  behind  them. 

Observation  can  be  carried  on  by  a  man  crouch- 
ing below  the  parapet  and  making  use  of  mirrors 
properly  placed,  but  it  is  not  believed  that  any  great 
reliance  should  be  placed  on  this  method.  The  mir- 
rors are  too  delicate  for  the  rough  handling  incident 


-49— 

to  campaign  and  it  would  require  a  very  high -order 
of  intelligence  to  employ  them  effectively. 

Machine     Guns 

Machine  guns  are  now  an  accepted  and  very 
potent  factor  in  battlefield  operations,  and  provision 
for  their  efficient  use  in  the  trenches  must  be  made. 
Emplacements  must  be  so  constructed  as  to  afford 
maximum  protection  to  the  gun  detachment  consistent 
with  the  free  use  of  the  weapon.  Splinter  proof  over- 
head cover  is  desirable  and  should  be  provided  if 
practicable. 

Shelter  should  be  provided  for  both  gun  and  de- 
tachment when  not  engaged  in  firing.  The  guns  of 
a  platoon  should  be  spaced  about  twenty  feet  apart, 
and  adjacent  emplacements  should  be  connected  by 
a  communicating  trench. 

Drainage 

If  a  trench  is  to  be  occupied  for  any  length  of 
time,  especially  where  much  ground  or  falling  water 
is  to  be  encountered,  drainage  becomes  of  prime 
importance.  Many  years  ago  a  celebrated  military 
authority  asserted  that  "nothing  so  saps  the  courage 
of  a  soldier  as  to  wet  the  seat  of  his  trousers."  This 
may  be  accepted  as  a  true  maxim,  especially  in  cold 
weather,  and  the  trench  should  therefore  be  made  as 
dry  as  possible.  The  floor  of  the  trench  should  be 
given  a  sufficient  slope  to  the  rear  where  an  inter- 
cepting drain  should  collect  the  water  and  carry  it  to 
prepared  sumps  or  to  a  point  from  which  it  can  be 
disposed  of  by  drainage.  Provision  should  also  be 
made  for  excluding  surface  drainage  from  the 
trenches. 

Wat  e  r     Supply 

A  sufficient  supply  of  good  drinking  water  must 
be  assured  to  the  men  occupying  trenches.  The 


—50— 

arrangement  to  be  made  will,  of  course,  depend 
principally  upon  the  length  of  time  the  trench  is  to 
be  occupied.  Suitable  vessels  can  be  placed  in  the 
trenches  and  kept  filled,  or  water  for  filling  canteens 
can  be  distributed  at  stated  intervals.  In  soils  where 
water  is  easily  reached  wells  may  even  be  dug  in  the 
trenches. 

Night     Firing 

The  successes  of  the  Japanese  in  the  Russo- 
Japanese  war  have  given  a  wonderful  impetus  to 
night  operations  and  they  may  be  expected  to  play 
very  important  parts  in  the  wars  of  the  future.  On 
the  part  of  the  defense  this  will  necessitate  provision 
for  night  firing.  The  best  means,  of  course— and 
these  will  be  employed  by  both  attack  and  defense- 
are  searchlights.  Along  an  extensive  defensive 
front  it  is  not  believed  that  sufficient  searchlights 
will  ever  be  provided,  since  it  is  necessary  to  illumi- 
nate the  entire  extent  of  front,  due  to  the  fact  that 
information  is  lacking  as  to  the  point  which  the 
enemy  will  select  for  attack. 

If  there  is  sufficient  suitable  material,  bonfires 
can  be  prepared,  to  be  lighted  when  the  lookout  re- 
ports the  advance  of  the  enemy.  This  also  will 
seldom  be  practicable.  Other  means  of  illuminating 
the  foreground  are  star  shell  rockets,  such  as  were 
used  by  the  Russians  at  Port  Arthur,  and  illuminating 
pistols  for  firing  cartridges  of  port  fire  which  will 
burn  for  eight  or  ten  seconds. 

All  means  of  night  illuminations  being  uncertain, 
the  only  remaining  expedient  is  to  place  during  day- 
light rests  such  that  the  rifles,  when  placed 
upon  them,  will  sweep  a  desired  area  without  any 
aiming  on  the  part  of  the  soldier.  These  rests  may 
be  standards,  to  which  the  rifle  is  fastened  by  pins 
and  which  may  be  so  constructed  as  to  permit  of 


—51— 

adjustment  for  several  ranges,  or  they  may  be  simple 
battens  placed  lengthwise  along  the  parapet  so  that 
rifles  placed  upon  them  are  directed  at  the  desired 
area.  See  Fig.  22,  Plate  Vl-a. 

General 

No  magazine  arrangements  are  necessary.  As 
noted  in  Chapter  I,  ammunition  for  immediate  use 
may  be  placed  upon  the  elbow  rest.  Recesses  may 
be  constructed  in  the  parapet  and  in  the  shelters  in 
which  boxes  of  small  arms  ammunition  may  be 
placed. 

As  far  as  practicable,  telephonic  communication 
should  be  provided  throughout  the  trenches. 

In  loose  soils  or  sand  great  difficulty  will  be 
encountered  in  making  slopes  stand  at  the  desired 
angles.  Revetment  should  be  resorted  to  if  prac- 
ticable. Figs.  23  and  24,  Plate  Vl-a,  show  a  method 
of  revetting  with  any  available  material,  such  as 
corn  stalks,  brush,  etc.  For  more  elaborate  methods 
of  revetment,  see  Engineer  Field  Manual,  19Q9,  page 
371  et  seq. 


Plate  V 


Via. 


Machine     Gur     Emplacement 


Fig.21 


Fig.21b. 

P|an  Sectron  A-B 


Fig.21c. 

Section   C-D 


Sod  Cover 


Crushed  Stone 


Fig.22a.  Fig. 22  b.         Fig.22c 


F,3.23     >\ 


J.H. 


Chapter     IV 

ACCESSORY  FEATURES  IN  REAR  OP  THE  FIRE   TRENCHES. — 
SHELTERS  FOR  THE  SUPPORTS  AND  RESERVES,  COM- 
MUNICATIONS, OBSERVATION  STATIONS,  EM- 
PLACEMENTS FOR  ARTILLERY,  LATRINES, 
DRESSING  STATIONS,  ETC. 

T  T  7E  have  seen  that  fortified  positions  must  have 
*  ^  sufficient  depth,  as  otherwise  the  line  is  too 
easily  pierced.  This  depth  is  secured  by  the  location  of 
the  supports  and  the  sector  and  the  general  reserves. 
This  organization  in  depth  calls  for  the  employment 
of  certain  accessory  features  in  rear  of  the  fire 
trenches,  and  these  we  will  now  discuss. 

It  will  frequently  be  the  case  that  the  character 
of  the  terrain  is  such  as  to  afford  natural  or  existing 
artificial  cover  for  supports  and  reserves  by  which 
they  are  shielded  from  the  view  of  the  enemy,  and, 
to  a  greater  or  less  extent,  protected  from  h;s  fire. 
It  may  even  be  the  case  that  ravines,  folds  in  the 
ground  and  existing  concealed  roads  furnish  in  addi- 
tion covered  approaches  from  the  above  concealed 
positions  to  the  fire  trenches.  Such  ideal  conditions, 
however,  do  not  by  any  means  always  exist,  and 
lacking  such  natural  cover  and  communications, 
troops  must  be  prepared  to  provide  them  for  them- 
selves. 

Trenches  for  protecting  supports  and  reserves 
are  called  cover  trenches,  and  those  connecting  the 
fire  and  cover  trenches  are  called  communicating 
trenches.  Fig.  1,  Plate  VII,  shows  the  relation  ex- 
isting between  the  three  classes  of  trenches. 

Supports  should  be  held  so  near  to  the  fire  line 
that  they  can  readily  reenforce  it  under  all  emergen- 
cies. This  may  compel  distances  as  small  as  fifty 

55 


-66— 

yards,  notwithstanding  the  fact  that  the  cover 
trenches  then  come  inside  the  dispersion  area  of 
artillery  fire  directed  at  the  fire  trenches.  The 
prompt  reenforcement  of  the  firing  line  at  the  critical 
moment  is  a  delicate  matter.  The  enemy's  artillery 
fire,  having  supported  his  infantry  at  the  decisive 
range,  will  be  next  extended  to  cover  the  rear  of  the 
position.  It  is  just  at  this  moment  that  the  supports 
will  be  wanted  to  reenforce  the  fire  trench.  If, 
therefore,  the  supports  are  placed  too  far  to  the  rear 
they  not  only  may  not  arrive  in  time,  but  to  come  up 
at  all  will  need  cross  ground  liable  to  be  swept  by 
artillery  fire.  Reserves,  both  sector  and  general, 
must  be  so  located  that  they  can  reach  all  equally 
important  parts  of  the  fire  line  with  equal  facility, 
or  that  the  length  of  time  necessary  for  them  to 
reach  any  point  is  an  inverse  function  of  the  im- 
portance of  that  point.  The  reserves  should  gen- 
erally be  placed  far  enough  to  the  rear  to  escape  the 
effect  of  "overs"  from  hostile  artillery;  that  is,  not 
nearer  than  300  yards. 

Cover  trenches  for  supports  and  reserves  differ 
from  fire  trenches  in  that  they  are  not  ordinarily  de- 
signed to  deliver  fire  but  are  merely  for  protection 
of  the  soldier  pending  his  taking  an  active  part  in 
the  engagement.  They  should  afford  him  the  maxi- 
mum of  shelter  and  comfort,  and  give  him  a  ready 
means  of  egress.  To  fulfill  the  latter  requirement, 
trenches  may  be  provided  with  sortie  steps  to  permit 
the  occupants  to  advance  on  a  broad  front  and  with- 
out loss  of  time.  The  amount  of  protection  afforded 
is  dependent  upon  time,  materials,  and  the  equip- 
ment and  condition  of  the  troops,  varying  from  the 
simplest  mound  of  earth  to  trenches  with  complete 
overhead  cover.  Types  are  illustrated  by  Figures  2 
and  3,  Plate  VII.  There  is  no  limit  to  the  number  of 
styles  of  cover  behind  the  fire  trenches,  involving 


—57— 

the  existing  or  natural  features,  the  work  of  the 
troops,  and  a  combination  of  these  two. 

The  cover  trenches  being  provided,  the  next 
thing  to  do  is  to  give  the  troops  a  safe  passage  from 
them  to  the  fire  trenches.  Communicating  trenches 
are  intended  merely  for  the  concealment  of  the  man 
while  passing  through  them.  Not  being  continually 
occupied,  and  it  being  impossible  for  the  enemy  to 
discover  whether  he  is  doing  any  real  damage  to 
them  by  artillery  fire,  there  is  not  much  chance  of 
their  being  subjected  to  a  regular  bombardment, 
hence  men  passing  through  are  exposed  to  chance 
shots  only.  Of  course,  the  communicating  trenches 
must  not  be  enfiladed  by  the  enemy,  and,  therefore, 
the  trace  of  such  trenches  should  make  an  angle 
with  (i.  e. ,  not  be  parallel  to)  the  enemy's  fire.  Where 
this  cannot  be  done  the  communicating  trenches  may 
be  defiladed  by  traverses,  or  they  may  be  entirely 
covered  over,  as  in  the  case  of  a  communicating 
trench  leading  to  a  fire  trench  some  distance  down  a 
forward  slope.  The  earth  excavated  from  the  trench 
is  usually  piled  up  on  the  side  toward  the  enemy, 
sometimes  it  is  piled  on  both  sides.  Figure  4,  Plate 
VII,  illustrates  a  form  of  communicating  trench. 

As  regards  both  cover  trenches  and  communicat- 
ing trenches  we  must  not  lose  sight  of  the  fact  that 
the  usual  time  will  not  permit  of  their  construction 
on  the  field  of  battle  and  we  will,  therefore  be  lim- 
ited to  making  the  best  of  any  natural,  or  existing 
artificial  accidents  of  the  terrain.  Every  effort 
should  be  made  to  improve  these  however,  without 
imposing  an  exhausting  amount  of  work  upon  the 
troops.  The  same  necessity  for  concealment  applies 
to  these  trenches  as  to  the  fire  trenches,  but  in  a 
somewhat  lesser  degree.  Both  cover  and  communi- 
cating trenches  may  sometimes  overlook  the  fore- 
ground in  portions  of  their  length  and  may  then  be 


-38- 

used  to  reenforce  the  firing  line  by  providing  a  firing 
step  on  such  portions. 

Where  the  communicating  trenches  change  di- 
rection, returns  can  be  constructed  and  made  use  of 
for  latrines  and  for  the  establishment  of  collecting 
stations,  as  shown  in  Fig.  1,  Plate  VII.  These  should 
of  course  be  given  the  most  effective  cover  possible, 
the  collecting  stations  particularly  demanding  over- 
head cover.  The  construction  employed  will  be  in 
all  respects  similar  to  that  used  in  the  trenches. 

Notwithstanding  the  many  scientific  adjuncts 
made  use  of  in  military  operations,  it  must  not  be 
forgotten  that  war  is  in  reality  a  very  elementary 
affair,  and  that  ruses  will  be  as  effective  today,  if 
well  planned,  as  they  were  in  earlier  times.  For  this 
reason  dummy  trenches  should,  whenever  practicable, 
be  made  use  of.  They  deceive  the  enemy  both  as  to 
the  location  and  as  to  the  number  of  the  defenders. 
These  trenches  should  be  made  to  simulate,  as  nearly 
as  possible,  real  trenches  in  every  way,  but  should 
be  somewhat  more  conspicuous.  They  should  be  lo- 
cated in  rear,  rather  than  in  advance  of  the  fire  line, . 
but  at  the  same  time,  they  should  be  so  placed  as 
not  to  subject  either  supports  or  reserves  to  chance 
shots.  Much  use  was  made  of  dummy  trenches  in  the 
Boer  War,  and  the  Japanese,  especiallly,  made  great 
and  effective  use  of  them  in  deceiving  the  Russians. 
Even  a  furrow  run  with  a  plow  will  at  long  and  mid- 
ranges  present  the  appearance  of  a  trench. 

One  of  the  most  essential  requirements  of  a  for- 
tified position  is  that  easy  communication  must  exist 
everywhere  in  rear  of  the  firing  line.  To  this  end, 
roadways  as  good  as  practicable,  must  be  prepared, 
over  which  reserves  can  be  moved  very  speedily  in 
any  desired  direction.  Streams  must  be  bridged 
and  ravines  either  bridged  or  the  banks  scarped 
down.  Guide  posts  must  be  set  up  for  day  use,  and 


—59— 

lanterns  for  night,  to  insure  troops  taking  the  proper 
directions.  The  character  of  these  works  is  so  ob- 
vious that  nothing  more  than  a  reference  to  them  is 
deemed  necessary. 

Telephonic  communication  must  be  provided 
throughout  in  order  that  all  operations  may  be  prop- 
erly coordinated. 

If  time  suffices,  covered  stations  must  be  pro- 
vided for  commanding  officers.  Nothing  is  so  apt  to 
demoralize  a  force  as  to  be  deprived  at  a  critical 
moment  of  its  directing  genius.  Any  form  of  cover- 
ed observation  station  such  as  shown  in  Figs.  19  and 
20,  Plate  VI,  Chap.  Ill,  will  be  suitable  for  the  pur- 
pose. Very  conspicious  hill  tops  are  not  so  well 
adapted  for  stations  for  commanding  officers  as 
points  which  are  less  prominent  but  still  afford  a 
satisfactory  view.  The  Commanding  General  of  the 
Japanese  XI  Division  was  severely  wounded  at  Port 
Arthur  while  in  an  observing  station  located,  on  a 
conical  hilltop. 

No  discussion  of  the  accessory  features  in  rear 
of  the  fire  line  would  be  complete  without  reference 
to  the  artillery  positions.  In  many  cases  the  guns 
can  be  placed  in  numerous  positions  concealed  from 
view  and  employing  indirect  fire,  and  here  no  artifi- 
ficial  cover  is  essential.  In  other  cases  the  artillery 
will  not  be  so  fortunate,  and  artificial  means  of  pro- 
tection for  both  guns  and  men  will  be  needed.  This 
is  especially  necessary  in  so-called  '  'dagger  bat- 
teries/* i.e.,  concealed  guns  placed  well  to  the  front, 
ready  to  open  fire  at  critical  moments  on  a  line  of 
advance  or  a  restricted  area. 

The  simplest  protection  that  can  be  given  is  to 
fill  in  with  earth  the  gap  between  the  ground  and 
the  bottom  of  the  shields.  If  more  time  is  available, 
protection  for  the  gun  crew  may  be  given  as  shown 
in  Figure  5,  Plate  VII.  In  this  case  no  shelter  is 


—60- 

provided  for  the  gun,  ammunition  may  be  stored  in 
the  shelter  for  the  men,  and  the  caisson  may  be 
placed  as  shown.  Any  additional  time  will  be  utili- 
zed in  completing  the  pit  as  shown  in  Figure  6,  Plate 
VII,  thereby  rendering  the  gun  fairly  safe.  If  it  is 
known  from  the  first  that  time  will  be  available,  the 
gunpit  shown  in  Figure  7,  Plate  VII,  might  well  be 
built,  the  ammunition  being  stored  as  indicated  and 
the  limbers  hauled  back  to  a  place  of  safety.  Adja- 
cent gun  pits  should  be  connected  by  communicating 
trenches  arranged  so  that  a  continuous  parapet  will 
be  presented,  thus  making  it  more  difficult  for  the 
enemy  to  locate  the  exact  positions  of  the  guns. 
Overhead  cover  for  the  cannoneers  is  desirable  and 
should  be  provided  if  practicable. 

The  above  refers  to  light  artillery  guns.  The 
heavy  artillery  will,  as  a  rule,  be  far  enough  to  the 
rear  not  to  require  any  work  for  its  protection. 
Should  exceptional  circumstances  render  artificial 
constructions  necessary,  they,  would  follow  very 
closely  the  gun  pits  given,  the  dimensions  being 
varied  to  suit  and  especial  attention  being  paid  to 
the  protection  of  the  ammunition,  it  being  very  valu- 
able and  its  destruction  by  a  chance  long  range  shell 
being  possible. 

Observation  stations  for  the  battery  commanders, 
and  the  higher  commanders  of  the  artillery,  must  be 
provided.  These  should  be  covered  if  practicable,  and 
provided  with  some  means  of  inter-communication. 

Dummy  gun  pits  will  be  especially  valuable  in 
drawing  the  hostile  artillery  fire,  and  a  simple  mound 
of  earth,  rapidly  thrown  up  with  a  log  protruding 
over  the  crest  will  serve  as  such. 


Plate   VII. 


Rifle    Trenches 

WiViVMViVA'Y.YV  •'.',• 


Fig. 2 

Reporting 

Cover  behind  a 
steep  Slope 


Cover    Trenches 
gj    Exit  Steps 


to, 


Section  a 


Fig.  7 


-*-  -\Ct.O-* 

Section  c.d.    Fig.  6. 


Chapter     V 

ACCESSORY  FEATURES  IN  FRONT  OF  THE  FIRE  TRENCHES.— 
CLEARING   THE    FOREGROUND.— DEMOLITIONS.— AD- 
VANCED   POSTS.— OBSERVATION    STATIONS. — 
RANGE  MARKS,  ETC. 

WE  have  seen  that  the  most  important  require- 
ment of  a  fortified  position  is  a  clear  field  of 
fire,  extending,  as  nearly  as  practicable,  to  the  effec- 
tive range  of  the  small  arm.  This  means  that 
everything  in  the  foreground,  not  of  use  to  the  de- 
fense and  which  may  be  of  use  to  the  enemy,  shall, 
so  far  as  circumstances  and  resources  permit,  be 
destroyed  or  its  character  so  altered  as  to  remove 
this  possibility  of  benefit  to  the  enemy.  This  organi- 
zation of  the  field  of  fire  is  known  as  "clearing  the 
foreground/'  and  includes  clearing  out  or  cutting 
down  and  removing  woods,  thickets  and  hedges; 
destruction  of  buildings,  stone  and  brick  walls; 
trampling  down,  or  otherwise  flattening  out  growing 
crops;  the  razing  of  earthen  mounds,  manure  and 
stone  piles,  and  the  filling  of  depressions.  The 
clearing  of  the  foreground  of  all  cover  limiting  the 
view  and  field  of  fire,  coupled  with  the  marking  out 
of  ranges,  is  more  important  than  all  other  defense 
arrangements.  Only  with  a  clear  view  and  un- 
obstructed field  of  fire  can  ones  own  fire. effect  be 
fully  developed. 

In  the  felling  of  timber  it  must  be  remembered 
that  it  will  be  necessary  to  cut  up  and  remove  the 
trees,  as  if  left  on  the  foreground  they  may  furnish 
excellent  cover  for  the  enemy.  For  this  reason, 
owing  to  lack  of  time  or  facilities,  it  will  often  be 

62 


—63- 

best  to  clear  a  wood  out,  leaving  the  large  trees 
standing.  This  will  especially  be  the  case  where  the 
foreground  has  an  uniform  slope  from  the  trenches, 
for  with  such  a  field  of  fire,  standing  timber,  without 
undergrowth,  will  neither  hinder  the  defense  nor 
favor  the  attack. 

Frame  buildings,  hay  stacks  and  other  combusti- 
ble objects  may  be  destroyed  by  fire,  but  this  method 
must  be  used  with  caution,  as  the  resulting  smoke 
may  obscure  portions  of  the  terrain  and  form  a 
screen  facilitating  the  approach  of  the  enemy. 
Buildings  and  structures  of  all  kinds  may  be  de- 
stroyed by  explosives,  but  care  must  be  exercised  in 
applying  this  method,  since  the  resulting  debris 
sometimes  furnishes  better  cover  for  the  ^nemy  than 
would  the  buildings  or  structures  if  left  standing. 

Standing  crops  can  best  be  leveled  by  some 
species  of  drag,  operated  by  man  or  animal  power. 
It  is  not  infrequently  the  case,  however,  that  stand- 
ing crops,  also  hedges  and  thickets,  constitute  suffi- 
ciently formidable  obstacles  to  render  their  destruc- 
tion by  the  defense  inadvisable,  and  the  relative 
value  of  the  better  field  of  fire  and  the  natural 
obstacle  should  be  weighed  before  making  decision 
as  to  the  disposition  to  be  made  of  such  natural 
features.  Crops  like  corn,  sugar  cane  and  kowliang, 
when  in  full  growth,  may  be  broken  down  about 
eighteen  inches  from  the  ground,  as  was  done  by  the 
Russians  in  Manchuria.  This  treatment  insures  a 
clear  field  of  fire  as  well  as  affording  a  natural 
obstacle. 

Given  a  clear  field  of  fire  up  to  and  including 
long  range  infantry  fire,  entrenched  troops  can  with 
their  fire  alone,  unaided  by  obstacles,  stop  the  most 
determined  attacks,  provided  the  disparity  of  forces 
is  not  too  great.  Such  an  ideal  field  of  fire  will  rarely 
be  found,  and  there  will  usually  be  portions  of  the 


—64- 
line  that,  owing  to  the  character  of  the  terrain,  the 
enemy  can  approach  under  cover.  In  this  case,  the 
enemy  having  approached  to  close  quarters  without 
appreciable  loss,  and  his  morale  being  consequently 
excellent,  it  is  questionable  whether  even  rapid  and 
accurate  fire  will  stop  him  in  the  short  remaining 
distance  he  has  to  travel.  It  is  therefore  advisable 
to  introduce  something  that  will  impede  his  progress 
and  thus  expose  him  for  a  longer  time  to  this  most 
effective  fire  of  the  defense.  In  cases  such  as  this, 
as  well  as  in  cases  where,  because  of  great  inferiority 
in  numbers,  a  purely  passive  defense  is  contemplated, 
obstacles,  if  practicable,  are  an  essential  component 
of  the  defensive  organization.  Their  object,  as  seen, 
is  to  protect  works  from  surprise,  to  reduce  the  mo- 
mentum of  an  attack  by  breaking  up  the  enemy's 
formations,  and  to  hold  the  enemy  under  the  most 
effective  rifle  fire  of  the  defense. 

To  accomplish  these  results  the  obstacles  should 
not  be  more  than  about  300  yards  from  the  fire  trench, 
for  if  placed  farther  away,  the  enemy,  while  destroy- 
ing them,  will  still  be  covered  by  the  fire  of  his 
artillery.  The  obstacle,  on  the  other  hand,  must  not 
be  closer  to  the  fire  trench  than  about  seventy-five 
yards,  for  if  the  enemy  gets  within  this  distance  be- 
fore he  is  stopped,  his  too  proximate  position  has  a 
most  disturbing  effect  upon  the  accuracy  of  fire  of 
the  defenders,  and  he  would,  in  addition,  be  able  to 
hurl  hand  grenades  with  considerable  effect.  Owing 
to  the  necessity  of  guarding  obstacles  at  night,  it  is 
advisable  to  locate  them  as  near  the  inferior  limit  as 
practicable. 

If  practicable,  obstacles  should  always  be  con- 
cealed, naturally  or  artificially,  since  there  is  thus 
introduced  a  most  disturbing  element  of  surprise  for 
the  enemy,  and  the  damage  or  destruction  of  the 
obstacles  by  artillery  fire  is  reduced  or  eliminated. 


—65  — 

Obstacles  are  sometimes  used  to  deny  to  the 
enemy  a  certain  line  of  approach  which  it  will  be 
difficult  for  the  defenders  to  cover  with  their  fire. 
In  this  case,  they  must  be  of  such  construction  that 
they  cannot  be  easily  destroyed. 

In  the  usual  case  of  field  fortification,  the  time 
available  will  permit  nothing  more  than  the  marking 
out  of  ranges,  digging  of  a  trench  and  some  clearing 
of  the  foreground,  but  the  value  of  obstacles  must  be 
thoroughly  appreciated  and  they  must  be  made  use  of 
whenever  possible,  if  the  circumstances  are  such  to 
render  their  use  desirable.  In  detached  posts,  where 
a  stubborn  defense  is  to  be  made  against  a  probable 
all-around  attack,  a  complete  circle  of  obstacles  is  in- 
dispensible. 

We  will  now  proceed  to  a  discussion  of  the  usual 
types  of  obstacles,  it  being  borne  in  mind  that  these 
are  merely  types,  furnishing  definite  ideals  which 
will  be  approached  as  nearly  as  time,  materials,  and 
other  considerations  will  permit.  The  fact  that  a 
commander  cannot  construct  obstacles  of  the  types 
shown  will  scarcely  be  an  acceptable  excuse  for  not 
making  the  best  possible  use  of  the  materials  and  re- 
sources of  which,  he  is  possessed. 

The  most  effective  obstacle  is  the  barbed  wire 
entanglement,  of  which  we  have  the  high  and  low 
types  shown  in  Figures  1  and  2,  Plate  VIII. 

In  the  high  wire  entanglement  the  pickets  are 
about  four  inches  in  diameter  and  about  six  feet 
long.  They  should  be  sunk  in  the  ground  about  two 
feet,  the  intervals  between  pickets  and  rows  being 
about  six  feet,  and  the  pickets  in  successive  rows 
being  staggered.  The  wire  is  then  fastened  to  the 
pickets  by  wrapping  or  by  wire  fencing  staples,  or 
both,  in  such  a  fashion  as  to  connect  the  top  and 
bottom  of  each  picket  with  the  tops  and  bottoms  of 
all  adjacent  pickets,  and  a  few  strands  are  run 


—66- 

around  irregularly.  A  regular  barbed  wire  fence, 
when  strongly  built,  will  also  serve  as  a  good  ob- 
stacle. It  may  be  used  alone  or  to  reenf orce  a  regu- 
lar entanglement. 

The  low  wire  entanglement  is  constructed  on  the 
same  general  idea,  the  pickets  being  lighter  and 
shorter  and  the  wire  connecting  only  the  tops.  The 
low  wire  entanglement  is  especially  useful  when  it 
can  be  placed  in  low  growing  vegetation  and  thus  be 
entirely  concealed  naturally.  Another,  and  very  ex- 
cellent form  of  the  low  wire  entanglement,  when 
concealed  by  vegetation,  is  constructed  by  driving 
the  pickets  with  their  heads  flush  with  the  ground 
surface,  and  leaving  considerable  slack  in  the  wire. 
Wire  entanglements  found  extensive  application  in 
the  South  African  and  Manchurian  wars:  When 
there  is  an  insufficient  supply  of  barbed  wire,  it 
should  be  used  for  the  front  and  rear  horizontal  wires, 
smooth  wire  being  employed  for  the  remainder. 

It  has  been  previously  mentioned  that  growing 
crops,  hedges  and  thickets  may  serve  as  obstacles. 
If  interlaced  with  barbed  wire,  they  become  very 
effective. 

Where  wire  is  scarce,  or  stakes  are  difficult  to 
obtain,  much  good  can  be  accomplished  by  the  use  of 
wire  nooses,  placed  in  the  grass  and  firmly  pegged 
down.  The  advancing  soldier  catches  his  foot  in  the 
noose,  draws  it  tight  around  his  leg  when  he  endeav- 
ors to  extricate  himself.  Considering  the  dangerous 
position  in  which  he  is  placed,  his  efforts  to  free  him- 
self will  take  sufficient  time  to  insure  his  being  put 
out  of  action.  See  Fig.  3,  Plate  VIII. 

Wire  entanglements  to  be  effective  should  have 
a  depth  of  approximately  thirty  feet.  The  wires 
should  not  be  strung  very  tightly,  as  this  will  facili- 
tate cutting.  This  class  of  obstacle  is  practically 
exempt  from  damage  by  artillery  fire,  and  will  have 


—67— 

very  general  application  on  account  of  the  extensive 
use  of  barbed  wire  and  the  consequent  ease  of  ob- 
taining it. 

Other  forms  of  wire  entanglements  are  shown 
in  Figures  4  and  5,  Plate  VIII. 

An  abatis  is  an  obstacle  presenting  the  sharp- 
ened ends  of  pronged  timber  to  the  enemy.  In 
felling  trees  they  may  be  dropped  towards  the  direc- 
tion of  hostile  approach,  left  attached  to  the  stump, 
the  foliage  and  smaller  branches  cleaned  off  and  the 
ends  of  branches  sharpened,  thus  forming  a  very 
efficient  abatis.  See  Fig.  6,  Plate  VIII.  Several 
rows  of  such  fellings,  the  tops  of  successive  rows 
overlapping  the  points  of  attachment  of  those  in 
front,  furnish  as  good  an  obstacle  as  can  be  desired, 
especially  if  interlaced  with  a  few  strands  of  barbed 
wire. 

Abatis  may  also  be  constructed  as  shown  in  Figs. 
7  and  8,  Plate  Villa,  small  trees  or  branches  being 
used.  Barbed  wire  will  here  too  add  much  to  the 
efficiency  of  the  obstacle.  Abatis  can  be  seriously 
damaged,  or  even  destroyed  by  artillery. 

Another  form  of  obstacle  is  the  shallow  and  deep 
pit.  While  they  have  had  much  use  in  the  past,  and 
the  Russians  employed  them  uniformly  in  their  de- 
fensive works  during  the  Manchurian  War,  their 
value  as  obstacles  is  hardly  sufficient  to  repay  the 
expense  of  construction.  A  low  wire  entanglement 
is  frequently  constructed,  covering  the  same  area  as 
the  pits,  and  a  somewhat  more  effective  article  is 
thus  created.  See  Fig.  9,  Plate  Villa.  The  deep 
pit  has  the  further  disadvantage  of  furnishing  close 
cover  for  the  enemy  if  he  succeeds  in  getting  into 
them. 

Two  forms  of  cheveaux  de  frise  are  shown  in 
Figures  10  and  11,  Plate  IX.  Any  and  all  parts  of 
them  may  be  of  metal  or  wood.  The  lances  are 


vm, 


i 


Tig. 2 


-2:25 


Fig. 3 


Fig. 6. 


\  HI  a. 


Fin. 7 


Fig.8 


Fia.9. 


IX. 


F,3.10 


Rg.ll 


K-28 

2S     -    r 


S 


S-i    Fig  12. 


-1C' 


F,3.16: 


Fig. 18 


IXa, 


'<          3'0         * 


Rg.14 


. 


JX 


Fig.15. 


—72— 

ordinarily  about  six  feet  long-.  This  obstacle  is  con- 
structed in  short  lengths,  for  ease  in  transportation, 
the  successive  short  lengths,  when  in  opposition,  being 
wired  or  chained  together.  This  obstacle  possesses 
the  great  advantage  that  it  can  be  made  under 
cover,  can  be  held  in  reserve,  and  can  at  any  time  be 
used  to  rapidly  close  the  hostile  avenues  of  approach. 

Figures  12  and  13,  Plate  IX,  show  similar  ob- 
stacles which  were  used  by  the  Japanese  and  Rus- 
sians in  their  late  war.  The  first  consists  of  tripods 
formed  by  binding  poles  together  at  their  middles 
with  wire,  these  tripods  being  then  placed  abutting 
and  secured  together  by  wire.  The  Russian  form 
consists  of  exaggerated  saw  bucks,  similarly  abutted 
and  bound  together.  A  form  of  wire  cheveaux  de 
frise  is  shown  in  Figs.  14  and  15,  Plate  IXa. 

Land  mines  may  be  made  use  of  as  obstacles, 
and  while  they  do  not  effect  much  actual  damage, 
their  moral  effect,  as  was  demonstrated  in  the 
Russo-Japanese  War,  is  very  great.  The  mines  may 
be  controlled,  contact,  or  a  combination,  depending 
upon  whether  their  action  is  intended  to  be  by  judg- 
ment firing,  automatic,  or  by  either  method  at  the 
will  of  the  defender. 

Figures  16  and  17,  Plate  IX,  show  simple  land 
mines  and  fougasses,  the  latter  being  designed  to 
throw  a  shower  of  stones  or  fragments  in  a  predeter- 
mined direction.  For  the  charges  to  be  used  in  land 
mines  and  fougasses,  see  Engineer  Field  Manual, 
1909,  pp.  414-415. 

The  natural  obstacle  offered  by  a  running  stream 
may  be  rendered  much  more  effective  by  damming 
the  stream  and  causing  an  area  of  overflow.  It  may 
also  be  possible  to  divert  some  stream  into  the  fore- 
ground and  thus  produce  the  same  effect.  Whether 
fordable  or  not,  such  an  inundated  area  will  be  a 
very  appreciable  obstacle  to  the  attack. 


-73— 

In  placing  obstacles,  it  must  always  be  kept  in 
mind  that  it  may  at  any  time  be  desirable  to  assume 
the  offensive,  and  provision  must  be  made  enabling 
the  defenders  to  do  so  without  being  impeded  by 
their  own  constructions. 

While  advanced  posts  must  be  used  with  great 
caution,  their  use  is  at  times  necessary,  for  instance 
to  afford  flanking  fire  over  otherwise  dead  spaces,  or 
to  occupy  some  point  which  must  be  forbidden  terri- 
tory for  the  enemy.  They  are  also  valuable,  when 
garrisoned  by  a  few  expert  riflemen  liberally  supplied 
with  ammunition,  in  bringing  early  upon  the  enemy 
so  effective  a  fire  that  he  will  be  compelled  to  deploy 
and  disclose  his  strength  and  intention^.  They  must 
.always  be  entrenched,  but  should  be  open  to  fire 
from  the  main  line  in  rear,  thus  preventing  their  oc- 
cupation by  the  enemy,  and  means  must  be  provided 
for  the  safe  withdrawal  of  the  garrison  to  the  rear. 
The  construction  of  these  advanced  posts  differs  in 
no  way  from  the  construction  of  ordinary  entrench- 
ments, except  that  they  are  usually  of  simpler  con- 
struction, and,  as  mentioned,  must  be  open  to  fire 
from  the  rear. 

It  may  be  desirable  to  have  a  few  advanced  ob- 
servation  stations,  to  give  early  information  of  the 
enemy's  movements.  These  should  be  constructed 
as  already  set  forth  in  Chapter  III,  and  should  have 
telephonic  connection  with  the  main  position. 

Elumination  of  the  foreground  has  already  been 
discussed  in  Chapter  III.  Where  this  is  not  prac- 
ticable, men  must  be  placed  in  observation  to  the  front 
at  night.  These  men  are  given  as  much  shelter  as 
practicable,  but  nothing  must  in  any  way  interfere 
with  their  seeing  and  hearing  in  every  direction. 
They  must  also  be  protected  from  the  fire  of  their 
own  side  as  it  will  be  impracticable  for  them  to  fall 
back  after  giving  the  alarm.  A  form  of  cover  for 


—74— 

an  advanced  night  sentry  is  shown  in  Fig.  18,  Plate  IX. 

One  of  the  great  advantages  of  the  defense  is 
that  the  engagement  takes  place  on  ground  which  is 
more  or  less  of  his  own  choosing,  and  about  the  fea- 
tures of  which  he  will  have  much  better  information 
than  the  enemy.  Of  especial  value  will  be  a  deter- 
mination of  ranges,  enabling  him  to  bring  an  effect- 
ive fire  upon  the  advance  as  soon  as  perceived.  This 
determination  of  ranges  is  second  in  importance  to 
nothing  else,  and  should  be  undertaken  at  once. 
There  will  usually  be  natural,  or  existing  artificial 
features  which  will  serve  sufficiently  to  identify 
ranges,  but,  lacking  these,  marks  must  be  estab- 
lished which  will  convey  the  desired  information  to 
the  defender  without  attracting  the  attention  of  the 
attack.  Such  marks  may  be  whitewashed  piles  of 
stone  or  stakes  with  markers  attached.  Every  com- 
mander of  a  sector  of  the  firing  line,  must  take  steps 
to  ensure  the  possession  of  sufficient  information 
concerning  ranges  to  enable  his  command  to  bring 
accurate  fire  on  every  portion  of  the  foreground 
within  effective  rifle  range. 

In  all  hasty  defensive  organizations  the  time  and 
means  available  will  limit  the  amount  of  work  that 
can  be  put  on  accessory  features.  Extensive  clear- 
ing of  the  foreground  involves  much  labor,  as  does 
also  the  construction  of  artificial  obstacles.  By  care 
and  judgment  in  locating  the  fire  lines  and  by  the 
utilization  of  natural  obstacles  much  can  be  accom- 
plished towards  securing  a  clear  field  of  fire  and  im- 
peding the  enemy's  advance  without  the  expenditure 
of  an  excessive  amount  of  labor  from  which  it  is  de- 
sirable to  spare  fighting  troops  as  much  as  possible. 


Chapter     VI 

EXECUTION   OF   FIELD   FORTIFICATIONS   BY   TROOPS.- -TOOL 
EQUIPMENT,  TASKS,  RELIEFS,  ETC. 

'TAHE  practical  execution  of  field  fortifications  de- 

-1  pends  upon   the  tool  equipment  of  the  troops, 

their  training,  and  upon  the  time  available  for  work. 

It  is  now  the  recognized  practice  to  equip  all 
troops  with  tools  and  appliances  for  the  execution  of 
different  classes  of  works  required  in  field  and 
fortress  warfare,  in  movements  and  in  encampments, 
and  the  proper  use  of  these  tools  and  appliances 
should  form  part  of  their  peace  instruction. 

The  ability  to  prepare  cover  quickly  and  under 
all  emergencies  is  now  regarded  as  so  important  that 
work  tools  should  form  a  part  of  the  portable  equip- 
ment of  the  troops  from  which  the  soldier  should 
never  be  separated  and  which  is  second  in  importance 
only  to  the  rifle  and  ammunition. 

In  order  to  reduce  weight  and  to  admit  of  greater 
convenience  in  carrying,  the  portable  tool  equipment 
is  considerably  lighter  and  smaller  than  the  cor- 
responding commercial  tools  which  necessarily  re- 
duces the  output  of  work.  In  addition  to  the  portable 
tools,  additional  tools  of  larger  size  and  of  special 
patterns  are  carried  in  the  combat  and  field  trains 
for  use  in  the  more  comprehensive  organizations  of 
the  terrain. 

As  a  result  of  the  experiences  of  the  South 
African  and  Manchurian  campaigns,  several  nations, 
notably  France,  Russia  and  Japan,  have  materially 
increased  the  tool  equipment  of  their  infantry. 

75 


—76— 

At  present  writing,  1914,  the  portable  tool  equip- 
ments of  the  leading  military  nations  is  as  follows: 

France,  1  tool  per  man  Germany,  1  tool  to  2  men 

Russia,  1  tool  per  man  England,    1  tool  to  2  men 

Japan,    1  tool  per  man  Italy,          1  tool  to  2  men 

Austria -Hungary,  nearly  one  tool  per  man 

The  portable  tool  equipment  of  the  United  States 
Infantry  is  fixed  by  General  Orders  No.  42,  War 
Department,  1913,  as  follows: 

For  each  squad  —1  pick  mattock,  with  carrier. 
1  wire  cutter,  with  carrier. 
3  shovels,  with  carriers. 
1  cutting  tool,  with  carrier. 

While  it  is  not  so  specifically  stated,  it  is  under- 
stood that  the  cutting  tools  are  to  be  one  half  hatchets 
and  one  half  machetes. 

The  following  is  the  recommendation  of  the 
Cavalry  Equipment  Board  for  the  portable  tool 
equipment  of  the  United  States  Cavalry,  which  has 
not  yet  received  the  approval  of  the  War  Department: 

"Each  man  carries  a  combination  picket -pin  and  handle 
for  intrenching  tool,  weight  1  Ib.  9  oz.,  case  4  oz.;  a  pick  head, 
weight  9  oz. ;  an  axe  head,  weight  1  Ib.  4  oz. ;  a  spade,  weight 
1  Ib.  1  oz.,  and  case  (including  case  for  pick  head  and  axe  head), 
weight  1  Ib.  The  picket-pin  serves  as  a  handle  for  all  three 
tools." 

The  proportion  of  cutting  to  intrenching  tools 
varies  between  wide  limits  in  the  different  armies, 
being  5  per  cent  in  the  German,  15  per  cent  in  the 
French,  and  50  per  cent  in  the  United  States.  The 
proportion  of  cutting  to  digging  tools  is  influenced  by 
the  character  of  the  country  in  which  it  is  likely  that 
war  may  be  waged.  European  armies,  operating  in 
thickly  settled  and  cleared  terrain  will  have  less  use 
for  cutting  tools  than  armies  operating  in  tropical  or 
sub-tropical  countries  with  their  dense  forest  and 
vegetable  growths.  Types  of  portable  intrenching 


—  77  — 

tools  in  use  by  different  armies  are  shown  in  Figs.  1 
to  6,  Plate  X. 

In  addition  to  the  portable  tools  carried  on  the 
person  of  a  soldier  a  further  provision  is  made  in 
the  combat  and  field  trains  of  the  several  infantry 
units.  Thus  in  France  each  infantry  regiment  has 
two  regimental  tool  wagons,  each  carrying  130  large 
shovels,  65  large  picks,  19  cutting  tools  and  a  small 
supply  of  explosives.  In  Germany  the  regimental 
combat  train  carries  30  large  shovels,  15  large  picks, 
15  hatchets,  24  axes  and  12  cross-cut  saws,  while  the 
regimental  field  train  carries  on  one  wagon  230  large 
shovels,  65  large  picks,  30  axes  and  8  saws.  In  most 
of  the  foreign  armies  there  is  still  another  echelon  of 
large  sized  tools  in  the  engineer  park. 

Under  the  provisions  of  General  Orders  No.  42, 
War  Department,  1913,  the  following  equipment  of 
park  tools  is  laid  down  for  a  regiment  of  infantry: 

Axes 26 

Crowbars : 7 

Nails,  Ibs.  95 

Pick  mattocks.,  149 

Sandbags 450 

Saws,  hand 13 

Saws,  two-man 13 

Shovels 298 

Wire,  Ibs _  25 

Carborundum  wheel 1 

Saw  set  (for  hand  saws) 1 

Saw  tool  (for  two- man  saws) 1 

Saw  files 6 

(Containers  are  furnished  for  files,  nails,  and  all 
edged  tools.) 

This  regimental  equipment  is  carried  on  one  field 
wagon  furnished  for  the  purpose.  The  tool  wagons 
of  a  division  will  be  consolidated  into  a  park,  under 
the  charge  of  the  chief  engineer  of  the  division. 

Under  the  provisions  of  General  Orders  No.  63, 
War  Department,  1913,  each  machine  gun  platoon 
has  certain  digging  tools  furnished  by  the  Ordnance 


—78- 

Department,  which  will  be  available  for  entrenching. 
The  following  is  the  prescribed  park  tool  equip- 
ment for  a  regiment  of  cavalry  (see  General  Orders 
No.  42,  War  Department,  1913): 

Axes ... 52 

Shovels '_  _  56 

Pick  mattocks 52 

These  tools  are  carried  upon  the  squadron  com- 
bat wagons  and  upon  the  field  wagon  of  the  machine 
gun  troop. 

No  special  entrenching  tools,  either  portable  or 
park,  are  provided  for  the  field  artillery. 

In  the  execution  of  field  fortifications  the  avail- 
able time,  the  training  of  the  troops  and  tool  equip- 
ment are  governing  factors.  In  hasty  works  the 
portable  tools  of  the  infantry  will  usually  be  the 
main  reliance  of  the  troops  but  may  be  supplemented 
by  the  large  tools  of  the  trains  and  tools  requisitioned 
locally  (from  villages  and  farms  close  at  hand). 

In  the  construction  of  rifle  trenches  the  company 
forms  the  normal  working  unit.  The  company  com- 
mander, assisted  by  the  platoon  and  squad  leaders, 
marks  out  the  line  of  trench,  determines  the  height 
of  the  parapet  and  the  location  of  traverses.  The 
location  of  the  line  of  the  excavation  is  most  con- 
veniently marked  on  the  ground  by  the  squad  leaders 
laying  their  packs  on  the  ground  or  by  sticking 
their  bayonets  into  it.  The  men  provided  with 
intrenching  shovels  are  then  deployed  on  the  line 
and,  after  being  properly  posted,  each  man  forces 
his  intrenching  tool  into  the  ground  close  to  his  feet, 
thus  marking  the  left  (or  right)  limit  of  his  task. 
The  men  then  step  back  several  paces,  unsling  and 
lay  down  their  packs,  pick  up  their  rifles  and  a  couple 
of  cartridge  clips  and  deploy  anew  on  the  line  marked 
out.  Each  man  lays  his  rifle  on  the  ground  behind 
him  and  then  commences  work.  If  an  attack  is  likely 


7Q 

t   J7      ~ 

during  the  progress  of  the  work,  the  first  efforts 
should  be  directed  towards  securing  a  parapet  of 
sufficient  height  to  afford  cover  for  the  head  and  a 
support  for  the  rifle  in  the  lying  down  position,  after 
which  the  trench  is  gradually  deepened  to  the  final 
requirements  of  a  standing  trench,  the  work  being 
so  regulated  that  the  trench  may  at  all  stages  be 
usable  for  defense.  Men  may  be  posted  5  feet  apart 
by  taking  intervals  with  both  arms  extended  and 
hands  closed  and  3  feet  apart  by  taking  intervals 
with  one  arm  extended,  hand  closed.  Dimensions  of 
rifle  trenches  may  be  laid  off  with  the  intrenching 
tools,  which  are  22  inches  long. 

If  actually  under  fire  and  unable  to  work  in  a 
standing  position  a  rifle  trench  may  still  be  con- 
structed by  the  men  working  in  pairs,  one  using  his 
intrenching  tool  to  excavate  a  shallow  trench  on  his 
right  side  and  heaping  up  the  earth  so  obtained  to 
gain  cover  for  his  head  and  a  rest  for  his  rifle  while 
his  comrade  keeps  on  firing.  Duties  are  exchanged 
from  time  to  time  by  passing  the  intrenching  tool 
back  and  forth,  one  man  digging  and  the  other  firing 
until  gradually  a  standing  trench  is  secured.  The 
method  of  executing  a  trench  under  fire  is  shown  in 
Fig.  7,  Plate  X. 

If  the  ground  be  too  hard  to  admit  of  the  easy 
insertion  of  the  intrenching  shovel  it  will  be  advan- 
tageous to  first  loosen  the  earth  with  the  pick. 
There  being  but  one  pick  per  squad  it  will  either 
have  to  be  used  in  turn  by  each  of  the  three  shovel- 
ers  or  else  one  man  may  be  detailed  to  do  all  the 
picking  for  the  three  shovelers,  working  from  one 
end  of  their  combined  tasks  to  the  other,  each  shov- 
eler  in  turn  stepping  from  the  trench  and  resting 
while  the  man  with  the  pick  is  employed  in  the  limits 
of  the  shoveler's  task. 


—80— 

Squad  leaders  supervise  their  squads,  seeing  that 
the  work  progresses  as  quickly  as  possible,  that  the 
desired  dimensions  are  attained  and  that  the  trench 
is  made  as  inconspicuous  as  possible.  Platoon  com- 
manders see  that  the  work  of  their  squads  proceeds 
uniformly,  apportion  assistance  to  any  squads  ex- 
periencing delay,  see  that  squad  leaders  are  familiar 
with  the  ranges  determined  to  recognizable  points  of 
the  foreground,  cause  observation  of  the  foreground 
to  be  maintained  if  the  enemy  is  close  at  hand  and 
arrange  for  the  occupation  of  the  trenches  when 
finished. 

The  company  commander  is  responsible  for  the 
correct  location  of  the  trench  or  trenches  and  sees 
that  important  ranges  are  determined  for  the  infor- 
mation of  his  company  and  arranges  for  the  occupa- 
tion of  the  trenches  when  completed. 

The  foregoing  is  the  general  method  followed 
when  intrenching  must  be  carried  out  in  the  imme- 
diate presence  of  the  enemy  or  under  his  fire. 

When  more  time  is  available  the  portable  tools 
will  be  replaced  or  supplemented  by  the  tools  of  the 
trains  or  requisitioned  in  the  vicinity  and  more  care 
can  be  taken  in  siteing  the  trenches  and  accurately 
posting  the  workmen. 

The  rate  of  progress  depends  upon  the  interval 
between  workmen  as  well  as  on  the  character  of  the 
tools  employed.  The  portable  intrenching  shovel  is 
incapable  of  the  same  output  of  work  as  the 
larger  tools  of  the  train  or  regular  commercial 
models,  but  its  shorter  handle  permits  of  men  work- 
ing at  smaller  intervals  than  do  the  larger  tools. 
For  convenient  working  with  the  larger  tools  an 
interval  of  five  feet  between  workmen  is  about 
as  small  as  can  be  used,  while  with  the  portable  tools 
men  can  work  at  interval  of  three  feet  (even  two  and 
one-half  feet  being  stipulated  in  the  regulations  of 


—81— 

foreign  armies).  Roughly  speaking,  it  may  be  as- 
sumed that  the  time  necessary  to  complete  a  trench 
with  the  portable  tools  with  the  men  at  three  foot 
intervals  is  about  the  same  as  with  the  larger  tools 
with  men  at  five  foot  intervals. 

Since  only  a  portion  of  the  company  is  equipped 
with  intrenching  shovels,  all  the  men  cannot  be  put 
to  work  digging  simultaneously.  In  the  French  ser- 
vice there  are  160  intrenching  shovels  per  company 
and  with  three  feet  intervals  486  feet  of  trench  can 
be  dug  at  once.  This  is  sufficient  for  the  entire  com- 
pany, allowing  two  feet  of  trench  per  rifleman,  which- 
experience  has  shown  to  be  about  the  minimum  for 
the  most  convenient  use  of  the  rifle,  although  tests 
carried  out  by  the  Maneuver  Division  at  San  Antonio, 
Texas,  in  1911,  show  that  men  can  be  placed  as  close 
as  eighteen  inches  a/part  and  still  fire  satisfactorily. 

The  portable  tool  equipment  of  the  United 
States  service  furnishes  but  three  intrenching  shov- 
els and  one  intrenching  pick  to  a  squad  of  eight 
men.  The  length  of  trench  to  accomodate  a  squad 
should  be  about  sixteen  feet,  which  will  necessitate 
intervals  of  five  feet  if  each  squad  is  to  dig  its  own 
length  of  trench.  So  great  an  interval  for  the  port- 
able tool  will  entail  a  material  increase  of  time  in 
construction,  which  is  permissible  if  the  time  can  be 
spared.  Otherwise  two  squads  must  combine  to  dig 
one  squad  length  of  trench.  By  doubling  up  squads 
a  length  of  trench  for  half  the  company  can  be  very 
quickly  constructed.  Whether  the  diggers  shall  be 
posted  at  the  larger  or  smaller  intervals  and  more  or 
less  length  of  trench  in  greater  or  less  time  be  under- 
taken, must  be  determined  by  the  requirements  of 
the  situation. 

The  progress  of  the  work  is  also  affected  in  no 
small  degree  by  the  question  of  tasks.  With  long 
continued  exertion  the  output  of  work  falls  off  rap- 


—82- 

idly.  If,  therefore,  the  workmen  be  relieved  at  fre- 
quent intervals  better  progress  will  be  attained.  For 
hasty  works  executed  by  troops  under  great  pressure, 
perhaps  also  exhausted  by  marching  and  fighting, 
the  tasks  should  be  no  greater  than  can  be  accom- 
plished in  two  hours'  time.  This  will  conduce  to  a 
more  rapid  progress  of  the  work  and  will  conserve 
the  marching  and  fighting  powers  of  the  troops.  If 
double  gangs  be  employed  on  each  task,  the  gangs 
alternating  every  thirty  minutes  and  working  as 
rapidly  as  possible,  a  still  faster  progress  will  be  at- 
tained without  exhausting  the  men.  This  was  the 
method  employed  by  the  Japanese  in  Manchuria, 
each  gang  relieving  the  other  on  a  whistle  signal. 

Since  but  three  men  per  squad  will  be  equipped 
with  intrenching  shovels  in  our  service,  double  gangs 
can  readily  be  formed  in  each  squad  and  the  work 
thus  expedited.  Other  means  sometimes  available 
for  expediting  the  hasty  preparation  of  cover  are 
afforded  by  the  following: 

(a)  The  use  of  the  plow  to  run  a  few  furrows 
and  loosen  the  earth  to  a  depth  of  six  or  eight  inches. 
Plows  may  be  occasionally  found  convenient  to  hand 
at  nearby  farms,   to  which,  if  other  teams  are  not 
procurable,  the  teams  of  the  combat  train  may  be 
harnessed.     In  more  deliberate  works  extensive  em- 
ployment of  farm  and  road  making  machinery  may 
be  made  with  advantage.      By  suitably  modifying 
the  draft  rigging  a  plow  can  be  used  to  loosen  the 
earth  the  full  depth  and  width  of  rifle  trenches. 

(b)  By  incorporating  into  the  parapet  any  avail- 
able loose  material  such  as  fence  rails,  small  logs, 
stones  etc.     Such  material  can  be  gathered  up  and 
placed  by  the  men  not  actually  employed  in  digging. 

If  it  is  necessary  to  give  the  parapet  considerable 
command,  say  anything  over  one  and  one-half  feet, 
it  will  be  desirable  to  revet  the  interior  slope  of  the 


-83— 

excavated  material.  In  hasty  trenches  this  will 
ordinarily  be  limited  to  using  the  larger  lumps  and 
clods  of  earth  and  piling  them  up  as  steeply  as  they 
will  stand.  Provided  the  materials  are  available, 
a  form  of  hurdle  revetment  may  be  made  quite 
quickly  by  driving  stakes  at  intervals  of  three  or  four 
feet  and  placing  in  front  of  them  brush,  branches, 
cornstalk,  etc. 

In  the  interest  of  concealment  it  is  desirable  to 
save  the  sod  taken  from  the  excavated  area  for  cover- 
ing the  parapet.  In  hasty  work  this  will  not  always 
be  practicable  and  material  for  covering  the  parapet 
will  then  have  to  be  procured  by  men .  not  employed 
in  digging.  A  convenient  way  of  saving  the  sod  is 
to  cut  the  turf  into  strips  about  1'  wide  the  full  width 
of  the  parapet  and  then  roll  it  up  to  the  front. 
When  the  parapet^  is  completed  the  sod  is  simply 
rolled  back  on  the 'parapet. 

In  the  organization  of  a  supporting  point  formed 
of  a  group  of  trenches,  only  a  portion  of  the  tactical 
unit  assigned  to  the  defense  of  the  supporting  point 
will  be  employed  in  executing  rifle  trenches.  The 
men  not  assigned  to  work  on  the  fire  trenches  will  be 
employed  in  clearing  the  foreground,  constructing 
cover  and  communicating  trenches  for  supports  and 
reserves  and  in  gathering  material  for  head  and 
overhead  cover  in  case  the  latter  is  to  be  provided. 

The  time  required  for  the  execution  of  the 
different  classes  of  work  involved  in  hasty  field 
fortifications  depends  upon  the  tools  used.  It  has 
already  been  pointed  out  that  the  output  of  the  port- 
able digging  tools  is  about  three-fifths  of  that  of  the 
larger  tools  of  park  model.  Experience  has  shown 
that  the  average  output  per  hour  for  men  working 
with  large  tools  with  two  hour  reliefs  is  about  twenty 
cubic  feet  for  medium  soils  such  as  can  be  excavated 
without  a  pick.  If  the  workmen  be  spaced  at  inter- 


—84— 

vals  of  5'  the  time  required  for  constructing  any  type 
of  trench,  with  reliefs  not  longer  than  two  hours,  in 
medium  soil  will  be  the  quotient  of  the  number  of 
square  feet  in  the  cross  section  of  the  trench  divided 
by  four.  To  execute  the  same  work  with  the  port- 
able tools  in  the  same  time  the  men  must  be  posted 
at  intervals  of  three  feet,  or  else  a  longer  time  will 
be  required.  The  excavated  area  of  the  simple  stand- 
ing trench  is  7.4  square  feet,  hence  it  can  be  con- 
structed in  ordinary  soils  in  something  less  than  two 
hours'  time,  provided  men  are  posted  at  5'  intervals 
when  working  with  large  tools  and  at  3'  intervals 
when  working  with  portable  tools. 

The  character  of  the  soil  greatly  influences  the 
time  required  for  constructing  earth  covers.  In 
stony  or  rocky  soil,  the  time  will '  be  very  much  in- 
creased and  with  portable  tools  may  even  be  imprac- 
ticable. For  more  massive  profiles,  such  as  occur  in 
more  deliberate  organizations,  the  portable  tools  are 
of  little  use,  their  short  handles  making  it  impossible 
to  throw  excavated  material  any  distance.  Similarly 
the  portable  cutting  tools  of  the  infantry  are  suited 
only  to  light  work.  Any  heavy  work,  such  as  cutting 
down  of  large  trees,  demolition  of  structures,  etc., 
must  be  accomplished  with  the  large  tools  of  the 
combat  trains  or  left  to  the  engineers. 

The  most  important  fact  for  line  officers  to  re- 
member is  that  a  simple  standing  rifle  trench  can  be 
constructed  in  two  hours  or  less  with  the  portable 
digging  tools  of  the  infantry  and  that  two  hours' 
additional  work  with  the  same  tools  will  convert  this 
into  the  complete  standing  trench  shown  in  Fig.  5, 
Plate  I. 


Plate    X 


Fig  3  ' 

P'rench  Jointed    Saw. 


Fig. 2 

French 


Intrenching         Intrenching 


Shovel 


Pick 


Fig.  4 

U.S.  Intrenching 
Shovel 


R5.  5 

U  S. Intrenching 
Pick 


Fig.  6 
U.S.  Pioneer 
Pack  Shovel 


Mask 


r,c,7 


Execution  of  a   trench  by  two  men  in  prone  position 


—86— 


The  following  table  gives  the  approximate^time 
required  for  the  execution  of  the  more  usual  classes 
of  work  which  may  fall  to  the  infantry  in  campaign: 


Works 

Personnel 

Tools 

Time 

Simple  standing 

1  man  per  yd. 

Portable 

2  hours. 

rifle  trench  — 

Simple  overhead 

1  man  per  yd. 

Park  model 

2  hours  plus  time 

covers 

for  gathering  & 

bringing  up  ma- 

Cutting  down 

6   in.  diameter: 

2    axes   or    1 

3  minutes. 

trees 

2  men. 

jointed  saw 

12  in.  diameter: 

2  axes 

15  minutes. 

2  men. 

1  jointed  saw 

10  minutes. 

1  cross-cut  saw 

5  minutes. 

18  in.  diameter: 

2  axes 

30  minutes. 

2  men. 

1  cross-cut  saw 

12  minutes. 

Clearing  brush 

20  men:    300  sq. 

Saxes 

1  hr.  or  30  sq.  yds. 

yards 

5  bill  hooks 

per  tool. 

Abatis 

6    men     per    6 

1  axe,  1  saw 

2  hours. 

running     yds. 

1  bill  hook 

8    rows     trees 

deep 

Wire    entangle- 

Preparing 

2  axes,  1  saw 

3  min.  per  stake. 

ment 

stakes:    3  men 

Placing  wire:    6 

1  maul,3cutt'g 

1  hour. 

men  for  15  to 

pliers,  2ham- 

18  sq.  yds. 

mers.  staples 

In  prepared  positions  for  which  considerable 
time  would  be  available,  the  works  would  be  planned 
with  care  both  as  to  trace  and  profile  and  laid  out 
accurately  by  the  engineers.  The  construction  of 
such  positions  may  often  be  effected  wholly  or  partly 
by  civilian  labor  and  by  the  use  of  excavating  ma- 
chinery. Troops  will,  however,  be  frequently  called 
upon  to  assist  in  construction,  and,  in  such  a  case, 
their  work  would  be  supervised  by  overseers  fur- 
nished from  the  engineers  whose  functions  will  be 
limited  to  seeing  that  the  workmen  adhere  to  estab- 
lished lines  and  grades  of  the  works.  Officers  com- 
manding the  troops  employed  as  fatigue  parties  will 
alone  be  responsible  for  the  conduct  and  efficient 
working  of  their  men. 


Chapter     VII 

UTIILZATION  OP  ACCIDENTAL  FEATURES  OP  THE  TERRAIN. 
PRINCIPLES  OP  THE  ORGANIZATION  OF  VILLAGES, 
HOUSES,  WOODS,  ETC. 

THE  highest  expression  of  the  art  of  field  forti- 
cations  consists  in  the  utilization  of  the  natural 
strength  of  the  terrain  in  the  most  advantageous 
manner  with  the  minimum  means,  including  the 
avoidance  of  its  disadvantages. 

All  natural  screens,  covers,  obstacles  and  com- 
munications have  a  distinct  advantage  Vver  artificial 
creations,  not  only  in  the  relatively  smaller  amount 
of  work  required,  but  also  in  the  fact  that  troops 
will,  as  a  rule,  advance  from  them  more  readily  than 
they  will  from  purely  artificial  works. 

Existing  features  of  the  terrain  may  be  utilized 
either  as  screens  only,  as  covers,  or  as  both.  Some, 
like  road  and  railroad  embankments  and  cuts,  afford 
better  cover  than  any  artificial  construction  prac- 
ticable within  the  time  and  with  the  means  available 
in  the  field. 

Among  the  more  ordinary  features  of  the  terrain 
which  may  be  utilized  as  fortification  may  be  men- 
tioned walls,  hedges  and  fences,  buildings,  villages, 
woods,  road  embankments  and  cuts,  ravine  and 
stream  banks,  quarries,  etc.  All  these  features  are 
rarely  represented  on  the  ordinary  small  scale  maps 
used  in  directing  military  operations,  hence  the 
question  of  their  utilization  requires  a  certain  eye 
for  terrain,  skill  and  experience  in  utilization  of  its 
features  for  tactical  purposes  and  the  ability  to 
weigh  the  value  of  these  features  for  use  as  screens 
and  covers. 

87 


—88— 

The  utilization  of  existing  features  of  the  terrain 
for  fire  lines  requires  in  general  the  preparation  of  a 
firing  platform  to  permit  the  soldier  to  fire  standing 
with  a  good  view  of  the  foreground  and  a  convenient 
rest  for  his  rifle,  with  good  communications  along 
and  in  rear  of  the  fire  line. 

Individual  trees  or  bushes  usually  afford  insuffi- 
cient cover  against  the  penetration  of  rifles  and  ma- 
chine guns  and  must  be  strengthened  by  an  earth 
cover.  Dikes,  roads,  embankments  and  like  features 
constitute  excellent  fire  lines.  If  narrow,  the  fire 
line  should  be  organized  on  the  slope  away  from  the 
enemy  as  shown  in  Fig.  1,  Plate  XL  If  wide,  it  is 
better  to  construct  a  firing  trench  along  the  edge 
nearest  the  enemy  connected  with  the  rear  slope  by 
communicating  trenches  shown  in  Fig.  4,  Plate  XL 
If  a  railroad  track  occupies  the  top  of  the  embank- 
ment the  rails  will  make  a  good  firing  crest.  The 
railroad  embankment  skirting  the  Shoushanpu  ridge 
in  the  Russian  defenses  at  Liaoyang  formed  part  of 
the  Russian  fire  lines  and  was  strongly  held.  The 
same  embankment  was  also  used  as  cover  by  the 
Japanese  in  their  attack  against  Shoushanpu. 

Sunken  roads,  dry  water  courses,  quarry  walls 
and  like  features  are  organized  according  to  their 
nature  by  arranging  the  slopes  on  the  side  toward 
the  enemy  to  afford  a  firing  position  for  the  rifleman 
and  access  thereto.  Scarping  of  banks,  excavating 
steps,  providing  ramps  and  like  work  is  called  for. 

Figs.  2  and  3,  Plate  XI,  show  methods  of  organ- 
izing a  ravine  bank  and  road  ditch. 

In  case  the  feature  constitutes  a  good  obstacle, 
for  instance,  a  wet  ditch  with  muddy  bottom,  it  will 
be  better  to  construct  a  rifle  trench  some  distance  to 
the  rear.  Long,  straight  and  dry  ditches  with  steep 
banks  may  also  be  arranged  to  be  flanked  by  con- 
structing short  parapets  across  them  at  salient  and 


—89— 

reentrant  angles.  Examples  of  the  use  of  such  fea- 
tures are  afforded  by  the  sunken  road  at  Fredricks- 
burg,  the  gravel  pits  at  Gravelotte  and  numerous  in- 
stances of  dry  water-courses  in  the  Manchurian  cam- 
paign. 

All  classes  of  property  enclosures  may  be  made 
to  serve  as  screens  and  covers  as  well  as  obstacles. 
Hedges  make  excellent  screens  and  if  of  thorny 
growth,  such  as  osage  orange,  a  good  obstacle,  es- 
pecially if  interwoven  with  a  few  strands  of  barbed 
wire.  For  use  as  cover  they  require  the  addition  of 
an  earthern  parapet  on  the  side  away  from  the 
enemy  as  shown  in  Fig.  5,  Plate  XL  \0penings  for 
firing  through  the  hedge  should  not  be  spaced  too 
regularly  or  made  too  clear  cut  as  otherwise  they 
would  reveal  the  location  of  the  fire  line. 

Board,  picket,  barbed  wire  and  iron  fences  may. 
be  used  as  obstacles  by  moving  them  in  sections 
bodily  to  suitable  location,  or  else  their  material  may 
be  employed  in  providing  accessory  features  in  or  in 
rear  of  the  fire  trenches.  Close  board  fences  also 
serve  as  masks  and  may  be  used  as  revetment  for 
fire  trenches  by  throwing  up  an  earth  parapet  in 
their  front. 

Stone  and  brick  walls  afford  good  cover  if  suffi- 
ciently thick  (15  to  18  inches  for  rifle  bullets  against 
brick  walls).  The  provision  for  firing  platform  is 
regulated  by  the  height  of  the  wall,  several  forms  of 
installation  being  shown  in  Figs.  6  to  9,  Plate  XL 
High  walls  may  be  arranged  for  2  tiers  of  fire.  Stone 
walls  have  the  disadvantage  of  giving  a  dangerous 
splinter  effect,  to  diminish  which  it  is  well  to  cover 
their  tops  with  sod  or  sand  bags.  Stone  walls  are 
also  comparatively  easily  breached  by  light  field  guns 
at  medium  and  short  ranges.  When  the  wall  is  not 
too  high  an  earthern  parapet  in  its  front  as  shown  in 


-90— 

Fig.  10,  Plate  XI,  will  afford  reasonable  protection 
against  artillery  fire. 

Individual  buildings  have  ordinarily  only  a  lim- 
ited value  for  defense.  Unless  of  very  solid  con- 
struction their  walls  can  be  pierced  by  rifle  bullets  at 
mid  and  short  ranges  and  demolished  by  artillery. 
Notwithstanding  their  disadvantages  history  affords 
numerous  examples  of  stubborn  defense  from  strongly 
constructed  masonry  buildings.  Unless  dangerously 
exposed  to  artillery  fire  strongly  constructed  build- 
ings like  factories,  public  institutions,  churches,  etc., 
can  be  readily  organized  for  a  strong  defense  by  a 
few  men.  The  principal  works  to  be  carried  out  are 
the  closing  and  barricading  of  all  openings  on  the 
ground  floor,  including  cellar  openings,  arranging 
windows  and  doors  for  delivery  of  fire,  proper  ar- 
rangements for  flanking  fire  and  guarding  against 
conflagrations  by  removal  of  all  readily  combustible 
material  and  keeping  a  supply  of  water  on  hand. 

Villages  and  woods  constitute  the  larger  features 
of  the  terrain  which  frequently  find  application  as  a 
means  of  defense.  Notwithstanding  the  increased 
fire  effect  of  artillery  due  to  the  introduction  of  rapid 
fire  guns  and  howitzers  with  improved  ammunition, 
villages  and  woods  still  continue  to  serve  as  strong 
supporting  points  in  extended  lines  of  defense  and 
have  shown  themselves  capable  of  stubborn  defense 
in  the  most  recent  wars.  "All  the  explosive  shell  of 
an  entire  army  corps  will  not  suffice  to  demolish  a 
village"  says  General  Langlois  and  this  contention  is 
supported  by  the  experience  of  the  recent  campaign 
in  Manchuria  in  which  the  adobe  and  brick  villages 
of  the  Chinese  were  the  scenes  of  many  severe  com- 
bats. 

The  importance  of  villages  and  woods  depends 
essentially  upon  their  location  with  respect  to  the 
battle  lines,  their  nature  as  to  size  and  character  of 


-91— 

construction  or  growth  and  the  method  of  their  or- 
ganization. When  favorably  located  they  possess 
the  advantage  of  threatening  the  enemy's  line  of  ad- 
vance, flanking  our  own  defense  lines  and  when  suit- 
ably organized  form  supporting  points  in  the  whole 
defensive  organization.  Their  disadvantages  consist 
in  the  difficulty  of  directing  their  defense  and  the 
restriction  of  maneuvers  for  reenforcing  fire  lines  or 
making  counter  attacks. 

The  outer  edges  of  both  woods  and  villages  are 
easily  distinguishable  from  a  distance  and  afford 
good  targets  for  artillery,  hence  the  fire  line  should 
not,  in  the  interests  of  better  protection,  be  coinci- 
dent with  the  edges. 

In  the  organization  of  villages  for  stubborn  de- 
fense their  perimeters  are  sub-divided  into  tactical 
sections  (companies,  battalions)  care  being  taken  not 
to  use  main  entrance  roads  as  section  boundaries. 
From  §  to  |  of  the  entire  garrison  is  assigned  to  the 
section  defenses,  the  remainder  forming  the  general 
reserve  for  use  in  counter  attacking  the  enemy  in 
flank  or  for  covering  withdrawal.  Each  section  keeps 
out  a  section  reserve  and  organizes  its  front  line  into 
a  firing  line  and  supports.  The  strength  of  sector 
garrisons,  including  supports  and  local  reserves,  may 
be  calculated  at  1J  men  per  yard  of  perimeter. 

The  front  line  of  defense  of  a  village  is  now  or- 
dinarily placed  50  to  100  yards  to  the  front  of  the 
nearest  buildings,  using  simple  rifle  trenches  or  utiliz- 
ing any  suitably  located  property  enclosures  organi- 
zed as  already  indicated.  Where  the  village  is  not 
exposed  to  artillery  fire,  for  instance  when  located  in 
a  deep  and  narrow  valley,  the  outer  walls  of  the 
front  building  may  be  selected  for  the  outer  defense 
lines  and  these  buildings  prepared  for  defense.  The 
main  entrances  of  the  village  should  be  barricaded 


—92— 

strongly  and  the  main  approaches  held  under  heavy 
rifle  and  machine  gun  fire. 

Cover  for  supports  and  reserves  can  ordinarily 
be  found  behind  the  walls  of  inner  buildings.  For 
the  supports,  which  must  be  near  the  fire  line,  cover 
trenches  may  be  required. 

The  interior  communications  are  exceedingly 
important  in  the  defense  of  a  village.  Since  the 
main  streets  will  ordinarily  be  fire  swept  and  barri- 
caded, other  means  must  be  provided  for  securing 
freedom  of  movement  for  supports  and  reserves. 
Openings  must  be  made  in  inclosures  and  house 
walls  to  afford  short  and  direct  routes  to  the  various 
points  of  the  front  and  these  routes  must  be  numer- 
ous and  marked  by  sign  boards. 

As  in  all  other  cases,  the  front  fire  line  must  be 
located  so  as  to  command  the  foreground.  Detached 
buildings  in  front  of  the  main  fire  line  are  generally 
left  standing  if  they  do  not  limit  unduly  the  field  of 
fire. 

Interior  defensive  lines  may  be  organized  pro- 
viding the  village  offers  any  good  dividing  line 
generally  parallel  to  the  front.  A  wide  street  or 
stream  through  the  village  may  be  employed  for  this 
purpose.  In  any  event,  it  is  well,  always,  to  organ- 
ize defensively  one  or  more  strong  buildings  in  the 
interior  or  towards  the  rear  of  the  village  to  serve 
as  a  place  of  final  defense  after  the  front  line  shall 
have  been  pierced.  The  retention  of  such  a  group  of 
buildings  as  a  keep  greatly  facilitates  the  recapture 
of  the  village  by  the  outer  reserves. 

The  general  principles  governing  the  organiza- 
tion of  woods  are  much  the  same  as  in  the  case  of 
villages.  The  front  line  of  defense  may  be  placed 
some  distance  in  advance  of  the  outer  edge  or,  if  the 
woods  be  open,  a  short  distance  within.  The  latter 
location  is  especially  favorable  to  concealment,  but, 


—93— 

owing  to  the  roots  of  trees,  digging  is  more  difficult. 
If  the  woods  be  extensive,  troops  may  be  economized 
by  providing  abatis  along  portions  of  the  edge  and 
flanking  these  from  fire  trenches  located  at  salient 
angles.  Openings  should  be  left  between  the  abatis 
and  fire  trenches  to  permit  of  an  advance.  . 

Interior  defense  lines  may  occasionally  be  prac- 
ticable in  woods  along  the  banks  of  a  stream  or 
on  the  edges  of  a  clearing.  Owing  to  the  absence 
of  buildings,  keeps  rarely  enter  into  the  defensive 
organization  of  woods. 

The  most  important  measure  in  organizing  woods 
for  defense  is  the  preparation  of  interior  communi- 
cations. The  organization  of  these  should  actually 
precede  the  construction  of  the  lines,  for  without  the 
former  the  latter  will  be  of  little  value.  Roads  or 
paths  parallel  and  perpendicular  to  the  front  in  suffi- 
cient numbers  to  permit  ready  movement  of  supports 
and  reserves  must  be  constructed  and  will  call  for 
much  labor  if  there  be  heavy  undergrowth.  If  time 
permits  the  rear  edge  of  a  wood  may  be  obstructed 
by  slashings  to  delay  the  enemy  breaking  through 
and  give  them  time  for  counter  measures. 

While  woods  and  villages  may  be  readily  organ- 
ized for  a  stubborn  defense  perse,  their  tactical  value 
depends  upon  their  location  with  respect  to  the 
remaining  elements  of  the  defensive  line  as  well  as 
upon  the  adjacent  topography.  Their  value  is  some- 
times reduced  to  that  of  mere  screens  for  the  shelter 
of  sector  or  general  reserves.  Sometimes  their  loca- 
tion is  such  that,  while  not  vital  to  the  defense,  they 
may  be  made  to  serve  as  attractions  for  the  enemy 
and  thus  relieve  the  pressure  against  the  real  key 
points  of  a  position. 


Plate  XI 


Fia--7 


Fig. 10 


Chapter     VIII 

APPLICATION  OP  FIELD   FORTIFICATIONS  TO  THE   DEFENSE 

OF  THE  LINES  OF  COMMUNICATIONS. —BRIDGE 

HEADS. — BARRIER  WORKS. 

Defense     of     Lines     of 
Communications 

THE  uninterrupted  service  of  the  lines  of  com- 
munications is  of  vital  importance  to  the  ex- 
istence of  an  army  in  the  field  and  the'fr  protection 
consequently  a  matter  of  deep  concern  to  the  com- 
mander-in-chief.  The  front  of  operations  will, 
therefore,  usually  be  such  as  to  cover  the  lines  of 
communications  in  the  best  possible  manner,  that  is, 
normal  or  nearly  so  to  these  lines. 

But  when  the  lines  of  communication  are  long 
it  will  be  impossible  for  the  army  to  protect  them  by 
its  own  front  and  it  becomes  necessary  to  assign 
special  troops  for  this  duty.  It  will  be  manifestly 
impossible  to  protect  adequately  every  foot  of  a  long 
line  without  detaching  an  undue  proportion  of  troops, 
nor  is  this  necessary.  Attacks  on  the  lines  of  com- 
munications will  ordinarily  be  made  by  raiding 
parties  only,  whose  security  will  depend  upon  their 
mobility.  If  all  vital  points  of  the  lines  of  communi- 
cations, such  as  important  bridges,  viaducts,  tunnels, 
locks,  fuel  and  water  supplies,  etc.,  be  guarded,  the 
damages  which  a  raiding  party  can  bring  about  at 
other  points  will  be  relatively  insignificant.  The 
destruction  of  a  mile  of  track  (burning  of  cross-ties, 
bending  or  removal  of  rails,  etc.)  will  engage  the 
efforts  of  a  fair  sized  force  for  quite  a  time  and  yet 
such  damage  can  be  repaired  within  24  hours, 

95 


whereas  a  single  man  with  a  few  pounds  of  high 
explosives  can,  in  a  few  minutes  damage  a  bridge 
or  tunnel  so  as  to  cripple  the  lines  of  communications 
for  week  or  months. 

A  due  regard  for  economy  of  forces  therefore  in- 
dicates that  only  vital  points  of  the  line  of  communi- 
cations require  guarding  and  that  field  fortifications 
can  be  usefully  employed  for  this  purpose. 

The  service  of  the  lines  of  communication,  in- 
cluding their  protection,  devolves  upon  the  comman- 
der of  the  lines  of  communication  and  he  is  respon- 
sible for  their  defense  against  hostile  enterprises. 
The  troops  detached  for  this  purpose  are  under  his 
orders  and  may  comprise  all  arms  of  the  service. 

The  considerations  involved  in  the  application  of 
field  fortifications  to  the  protection  of  vital  points  on 
lines  of  communication  are  somewhat  different  from 
those  applicable  to  fortified  lines.  Since  the  attack 
may  come  from  any  or  all  directions  it  is  evident  that 
there  must  be  an  all  round  defense.  Furthermore, 
since  no  prolonged  systematic  attack  by  artillery  is  to 
be  feared,  the  importance  of  concealment  for  the  de- 
fensive works  is  less,  permitting  the  use  of  stronger 
profiles.  Since  the  defense  will  be  purely  passive, 
closed  works  with  ample  obstacles  will  be  in  order. 

As  in  all  other  defensive  organizations  the  works 
designed  for  a  defense  of  a  point  on  the  lines  of  com- 
munication .must  be  sited  so  as  to  give  the  greatest 
effect  to  the  weapons  of  the  defenders,  mainly  the 
rifle  and  machine  gun.  The  topography  will  there- 
fore dictate  the  location  of  the  works  and  this  may 
necessitate  placing  them  on  commanding  ground  at 
some  little  distance  from  the  object  to  be  defended. 
To  insure  the  immediate  protection  of  structures  like 
tunnels,  bridges,  viaducts,  etc.,  additional  works  will 
sometimes  be  needed  to  prevent  access  to  the  struc- 
tures by  individuals  or  small  parties. 


—97— 

Since  only  a  passive  defense  with  minimum  num- 
bers is  contemplated,  the  character  of  the  works  will 
be  such  as  to  permit  of  an  all  round  defense.  They 
will  therefore  consist  of  small  redoubts,  blockhouses, 
or  even  groups  of  trenches  surrounded  by  a  continu- 
ous line  of  obstacle.  For  the  protection  of  an  impor- 
tant bridge  the  defensive  arrangements  might  consist 
of  several  closed  defensive  points  on  each  bank,  occu- 
pying commanding  ground  and  a  good  all  round  field 
of  fire  with  the  addition  of  a  trench  or  blockhouse  at 
each  end  of  the  bridge.  To  prevent  access  to  the 
bridge  piers  and  abutments  by  boats,  the  piers  and 
abutments  should  be  held  under  fire  from  the  works. 
A  type  form  of  defensive  arrangements ^or-  the  pro- 
tection of  a  bridge  by  two  companies  of  infantry  is 
shown  in  Fig.  1,  Plate  XII.  The  defensive  arrange- 
ments for  tunnels  would  be  made  in  a  similar  manner, 
consisting  of  several  closed  defensive  points  on 
heights  adjacent  to  the  portals  with  a  blockhouse  or 
field  redoubt  at  each  portal. 

Blockhouses  are  small  bullet-proof  buildings 
roofed  in  to  protect  their  garrisons  from  the  weather. 
They  may  be  constructed  of  timber,  plate  iron,  rails, 
corrugated  iron  or  combinations  of  materials.  Timber 
alone  will  no  longer  stop  bullets  unless  of  extraordi- 
nary thickness  and  must  be  reenforced  by  earth  and 
metal.  A  simple  form  of  timber  blockhouse  with 
galvanized  iron  roof  is  shown  in  Fig.  2,  Plate  Xlla. 

Another  form  used  by  the  British  in  South  Africa 
is  shown  in  Fig.  3,  Plate  Xlla.  This  latter  was  con- 
structed of  corrugated  iron  drums  made  bullet-proof 
by  stone  and  gravel  packing  as  shown  in  the  figure. 
When  surrounded  by  a  continuous  obstacle  and  with 
entrances  secured,  blockhouses  of  the  type  described 
enable  their  small  garrisons,  12  to  20  men,  to  offer  a 
stubborn  resistance.  They  can  be  destroyed  only  by 


Scale  200yds=iin. 

Cl  Closed   Field    Work    for  3/4  Co 

b  Block   Mouse    for    XA  Co 

C  Trench    for   ICo. 

d  Communicating    Trench. 


XHa, 


B  I  ock    House 

used   by  British   in 

South      Africa 


Section  C-D 


- 100— 

artillery  with  which  only  large  raiding  parties  would 
be  supplied. 

When  field  redoubts  are  employed  on  the  defense 
of  the  lines  of  communication  they  will  be  of  small 
size  (for  garrisons  of  one  half  to  one  company)  and 
may  be  simple  ring  trenches  or  have  a  somewhat 
stronger  profile  as  shown  in  Fig.  4,  Plate  Xlla. 

The  defense  of  a  line  of  communications  involves 
not  only  the  security  of  points  vital  to  the  line  as 
discussed  above,  but  also  a  service  of  information, 
which,  in  connection  with  mobile  troops,  will  enable 
reinforcements  te  be  hurried  to  threatened  points. 
The  wireless  telegraph  is  especially  valuable  as  a 
means  of  reporting  the  near  presence  of  hostile  raid- 
ing parties  and  is  not  subject  to  interruption  like  the 
ordinary  telegraph  or  telephone  lines.  Whenever 
the  flatter  are  used,  any  interruption  'of  the  service 
must  be  taken  as  an  indication  of  the  presence  of  the 
enemy.  Mobile  columns  held  in  readiness  at  con- 
venient points  along  the  line  must  be  set  in  motion  as 
soon  as  the  enemy  makes  his  appearance  and  en- 
deavor to  defeat  his  attempts  at  injuring  the  line. 
On  railroads  such  mobile  columns  may  be  moved 
rapidly  along  the  line  on  special  armored  trains, 
carrying  machine  guns  and  artillery.  The  country 
on  either  side  of  the  line  should  also  be  observed  and 
patroled  to  some  distance  by  sentinels  and  cavalry  in 
order  to  give  timely  warning  of  the  enemy's  ap- 
proach. A  system  of  visual  signals  (heliograph  or 
flags  for  daytime,  rockets  or  signal  fires  for  night- 
time) should  be  established  as  a  means  of  communi- 
cation between  sentinels  and  the  garrisons  of  the 
defenses. 

Bridge     Heads 

Bridges  on  the  lines  of  communicattion  over  wide 
and  deep  streams  are  of  such  vital  importance  as  to 


—101— 

call  for  special  treatment.  Not  only  must  the  bridge 
structures  themselves  be  protected  from  all  pos- 
sible damage  but  provision  must  also  be  made  to 
cover  the  deployment  of  the  army  in  an  advance  and 
its  withdrawal  in  case  of  a  retrograde  movement. 
Field  works  constructed  to  meet  the  foregoing  re- 
quirements are  called  bridge  heads  and  consist  of  a 
line  of  works  enclosing  the  bridge  on  the  side  of  the 
enemy  and  located  at  such  a  distance  therefrom  as 
to  protect  the  bridge  structures  from  hostile  artillery 
and  to  enclose  sufficient  ground  to  insure  some  man- 
euvering power  to  the  army. 

The  principles  governing  the  organization  of  a 
bridge  head  are  the  same  as  those  governing  the  or- 
ganization of  defensive  lines  except  that  the  flanks 
of  the  bridge  head,  by  resting  on  the  stream  above 
and  below  the  crossing,  are  secure,  whereas  in  defen- 
sive lines  the  flanks  are  frequently  in  air.  Bridge 
heads,  being  intended  for  passive  defense  only,  will 
consist  of  works  more  strongly  organized  with  a  view 
to  economy  of  forces,  and  the  supporting  points  may 
be  closed  works. 

Stream  crossings  are  in  effect  nothing  but  short 
defiles  and  a  bridge  head,  therefore,  is  a  form  of  the 
defense  of  a  defile  at  its  exit,  that  is,  on  the  side  of 
the  enemy.  If  attacks  are  likely  to  be  made  on  the 
stream  crossing  from  the  side  of  the  stream  away 
from  the  enemy,  that  is,  on  the  entrance  to  the  de- 
file, a  line  of  works  should  be  constructed  on  this 
side  also.  When  a  stream  crossing  is  thus  defended 
on  both  sides  the  works  constitute  a  double  bridge 
head. 

For  large  armies  a  single  bridge  would  not  afford 
sufficient  means  for  crossing  a  stream  and  several 
bridges  would  be  required,  part  of  which  would  be 
military  bridges  specially  built  for  the  purpose.  The 
several  bridges  if  not  too  far  apart,  would  all  be  en- 


—102— 

closed  by  the  same  bridge  head,  as  was  the  case  of 
the  Russian  bridge  head  at  Liaoyang,  which  formed 
the  arc  of  a  circle  of  some  2J  miles  radius  and  cover- 
ed 7  bridges  including  the  railroad  bridge. 

Barrier     Works 

Barrier  works  are  such  as  are  designed  to  close 
defiles,  mountain  passes  or  stream  crossings  to  the 
enemy,  usually  on  the  flanks  of  a  field  army.  Closure 
of  defiles  may  be  effected  either  at  their  exits  or  en- 
trances, and,  in  the  case  of  mountain  passes,  in  their 
interiors  also.  When  it  is  a  question  of  a  purely 
passive  defense  the  best  location  for  barrier  works 
will  be  at  the  entrance  of  the  defile,  that  is  the  side 
away  from  the  enemy.  If,  however,  an  advance 
from  the  defile  is  held  in  view,  the  defense  must  be 
made  at  the  exit  and  should  enclose  sufficient  ground 
to  permit  of  deployment. 

The  principles  governing  the  construction  of  bar- 
rier works  are  similar  to  those  governing  the  con- 
struction of  bridge  heads.  The  works  in  general  will 
consist  of  a  line  of  supporting  points  affording  mutual 
support  and  organized  in  a  manner  similar  to  the  sup- 
porting points  in  a  defensive  line.  As  the  defense 
will  usually  be  passive  only  the  supporting  points 
will  be  strongly  organized  and  may  take  the  form  of 
closed  works  with  a  belt  of  obstacles. 


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